Armed Conflict in Syria: Overview and U.S. Response

February 27, 2018 (RL33487)
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The Syria conflict, now in its seventh year, remains a significant policy challenge for the United States. U.S. policy toward Syria in the past several years has given highest priority to counterterrorism operations against the Islamic State (IS, also known as ISIL/ISIS), but also included assistance to opposition-held communities, support for diplomatic efforts to reach a political settlement to the civil war, and the provision of humanitarian assistance in Syria and surrounding countries. The counter-IS campaign works primarily "by, with, and through" local partners, per a broader U.S. strategy initiated by the Obama Administration and continued with modifications by the Trump Administration. The United States has simultaneously advocated for a political track to reach a negotiated settlement between the government of Syrian President Bashar al Asad and opposition forces, within the framework of U.N.-mediated talks in Geneva. For a brief conflict summary, see Figure 2.

Since the recapture of the Islamic State's self-proclaimed capital at Raqqah by U.S.-backed forces in October 2017, Trump Administration officials have reemphasized that the United States is entering a "new phase" that will focus on "de-escalating violence overall in Syria through a combination of ceasefires and de-escalation areas." These efforts are designed to create the conditions for a national-level political process ultimately culminating in a new constitution and U.N.-supervised elections. In January 2018, Secretary of State Rex Tillerson laid out the Administration's policy for future U.S. involvement in Syria, stating that the United States intends to maintain a military presence there to prevent a resurgence by the Islamic State.

To date, the United States has directed nearly $7.7 billion toward Syria-related humanitarian assistance, and Congress has appropriated billions more to support security and stabilization initiatives in Syria and in neighboring countries. The Defense Department has not disaggregated the costs of military operations in Syria from the overall cost of Operation Inherent Resolve (OIR), which has reached over $18.5 billion. The executive branch has reprogrammed or requested more than $2.2 billion to train, equip, advise, and assist vetted Syrians as part of a specially authorized program in place since late 2014. Congress also has debated proposals to authorize or restrict the use of military force against the Islamic State and in response to Syrian government chemical weapons attacks, but has not enacted any Syria-specific use of force authorizations.

Looking forward, policymakers may consider questions regarding the purpose, scope, and duration of the U.S. military presence in Syria, the effectiveness of U.S. cooperation with Russia, post-Islamic State governance and reconstruction, as well as the challenges of reaching a political settlement between the Asad government and a broad spectrum of armed and political opposition actors.

Armed Conflict in Syria: Overview and U.S. Response


In March 2011, antigovernment protests broke out in Syria, which has been governed by the Asad family for over four decades. The protests spread, and were accompanied by escalating violence (primarily but not exclusively by Syrian government forces) and the formation of numerous political and armed opposition groups. President Obama in August 2011 called on Syrian President Bashar al Asad to step down. However, the rising death toll from the conflict, and the use of chemical weapons by the Asad government, intensified pressure for the United States and others to assist the opposition. In 2013, Congress authorized the provision of nonlethal assistance to elements of the Syrian opposition and debated the possible authorization of the use of force in response to an August 2013 chemical weapons attack in Damascus.

In 2014, the Obama Administration requested authority and funding from Congress to provide lethal support to vetted Syrians for select purposes. The Obama Administration's original request sought authority to support vetted Syrians in "defending the Syrian people from attacks by the Syrian regime," but the subsequent advance of the Islamic State organization and congressional debate resulted in a program focused on counterterrorism assistance. Congress authorized the Department of Defense-led program to combat terrorist groups active in Syria, defend the United States and its partners from Syria-based terrorist threats, and "promot[e] the conditions for a negotiated settlement to end the conflict in Syria."

In September 2014, the United States began air strikes in Syria, with the stated goal of preventing the Islamic State from using Syria as a base for its operations in neighboring Iraq. In October 2014, the Defense Department established Combined Joint Task Force-Operation Inherent Resolve (CJTF-OIR) to "formalize ongoing military actions against the rising threat posed by ISIS in Iraq and Syria." CJTF-OIR came to encompass the efforts of 70 countries and institutions, which contributed funds, personnel, and other support to the campaign. CJTF-OIR and coalition forces worked to bolster the efforts of local Syrian forces, including graduates of the Syria train and equip program, against the Islamic State. The United States also gradually increased the number of U.S. personnel in Syria, which reached roughly 2,000 by late 2017.

U.S. and coalition-backed forces in Syria succeeded in retaking, by the end of 2017, nearly all of the territory once held by the Islamic State. However, while U.S. efforts during this period largely focused on the defeat of the Islamic State, outside actors (Lebanese Hezbollah, Iran, and Russia) intervened to bolster Syrian government forces in their military campaign against opposition groups. The situation was compounded by conflict between local Syrian partners and other U.S. allies, the strengthening of Al Qaeda-affiliated groups among the opposition, and a regional humanitarian crisis. More than 5.5 million Syrians fled to neighboring states and beyond.

By early 2018, the collapse of IS territorial control in most of Syria was matched by significant military and territorial gains by the Syrian government. The U.N. has sponsored peace talks in Geneva, but they have largely failed to gain traction. It is unclear when (or whether) the parties will reach a political settlement that might result in a transition away from the leadership of the current regime, which U.S. officials have set as a prerequisite for the provision of reconstruction assistance. In the interim, U.S. officials have said that U.S. forces will continue to operate inside Syria for the purpose of preventing the reemergence of the Islamic State. Confrontations between pro-Syrian government forces and U.S. partners in Syria have resulted in a series of U.S. military strikes on progovernment forces since early 2017. Turkish military operations against the Kurdish enclave of Afrin in northwestern Syria are generating new challenges and risks, and Israel continues to conduct air strikes against what it describes as Iranian-affiliated targets in the southwest.

Figure 1. Syria: Map and Country Data


Size: 185,180 sq km (slightly larger than 1.5 times the size of Pennsylvania)

Capital: Damascus.

General Demographics

Population: 18 million (July 2017 est.)

Religions: Muslim 87% (official; includes Sunni 74% and Alawi, Ismaili, and Shia 13%), Christian 10%, Druze 3%

Ethnic Groups: Arab 90.3%, Kurdish, Armenian, and other 9.7%

Gross Domestic Product (GDP; growth rate): $24.6 billion (2014 est.); -36.5% (2014 est.)

Indicators of Humanitarian Need

People in need of humanitarian assistance: 13.1 million

Internally displaced persons: 6.1 million

Syrian refugees: 5.5 million

Unemployment rate: 50% (2017 est.)

Population living in extreme poverty: 69% (2018 est., UNOCHA)

Figure 2. Syria Conflict 2011-2017

Source: For sourcing and additional details, see the Appendix ("Conflict Synopsis").

Issues for Congress

Congress has considered the following key issues since the outbreak of the Syria conflict in 2011:

As the Syria conflict enters a new phase in 2018, following significant territorial losses by the Islamic State and military gains by the Syrian government, U.S. policymakers face a number of further challenges and potential decision points. These include the following:

The future of the Syria Train and Equip program. The Islamic State has lost the vast majority of the territory it once held in Syria. This has prompted uncertainty regarding the future of the Syria Train and Equip (T&E) program, whose primary purpose has been the counter-IS campaign. The FY2017 NDAA extended the program's authority through the end of 2018, but the FY2018 NDAA did not extend it further, asking instead for the Trump Administration to submit a report on its proposed strategy for Syria. In the coming months, Congress may consider whether to extend the Syria T&E authority and/or adjust its scope and authorized purposes to reflect developments on the ground. The Trump Administration is requesting $300 million in FY2019 Counter-ISIS Train and Equip Fund monies to continue U.S. partner assistance efforts.

The role of U.S. personnel in Syria. Congress has sought to clarify how long U.S. personnel will remain in Syria, for what purpose, and under what conditions they will be withdrawn.1 A series of U.S. force protection strikes against pro-Syrian government forces since early 2017 have highlighted the risk to U.S. personnel colocated with the SDF.

Administration officials have stated that the United States will maintain forces in Syria to prevent the reemergence of the Islamic State, while also noting the reduction of Iranian influence in Syria as a goal of U.S. policy.2 Asked to define the purpose of U.S. military personnel beyond the containment of the Islamic State, Acting Assistant Secretary of State for Near Eastern Affairs David Satterfield stated, "We are deeply concerned with the activities of Iran, with the ability of Iran to enhance those activities through a greater ability to move material into Syria."3 Members questioned whether any efforts by U.S. military personnel in Syria to counter Iranian activities would be covered by existing authorities.

Further complicating the issue, a February 2018 cross-border incident involving the reported penetration of Israeli airspace by a Syria-based Iranian drone and subsequent Israeli strikes on associated targets in Syria demonstrated the potential volatility that unchecked Iranian operations in Syria may create in the region.

Presidential Authority to Strike Syria Under U.S. Law4

A series of U.S. strikes on targets in Syria in 2017 reinvigorated debate in Congress over the authorization for the use of military force there. In an April 8, 2017, letter to Congress, President Trump stated that he had acted "pursuant to my constitutional authority to conduct foreign relations and as Commander in Chief and Chief Executive" in ordering the April 6, 2017, U.S. missile strikes on Al Shayrat airbase in Syria in response to a chemical weapons attack on Khan Sheikhoun. In the letter, President Trump says that he "acted in the vital national security and foreign policy interests of the United States," and that, "the United States will take additional action, as necessary and appropriate, to further its important national interests." On April 6, the President said he ordered the strikes to protect the "vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons." The April 8 letter expands upon this explanation.5

In the past, Presidents have justified the use of military force by relying on presidential powers they assert are inherent under Article II Commander in Chief and Chief Executive authority. The executive branch has claimed that a President may use military force to defend U.S. national security interests (even when an immediate threat to the United States and its Armed Forces is not necessarily apparent) and to promote U.S. foreign policy.

In 2017, the U.S. military used force against the Syrian government and their allies on limited occasions for force protection purposes, including for the protection of U.S. partner forces. In an August 2017 letter to Senate Foreign Relations Committee Chairman Senator Bob Corker, the State Department asserted that "the 2001 AUMF also provides authority to use force to defend U.S., Coalition and partner forces engaged in the campaign to defeat ISIS to the extent such use of force is a necessary and appropriate measure in support of counter-ISIS operations." The letter states

The strikes taken by the United States in May and June 2017 against the Syrian Government and pro-Syrian-Government forces were limited and lawful measures to counter immediate threats to U.S. or partner forces engaged in that campaign. The United States does not seek to fight the Syrian Government or pro-Syrian-Government forces. However, the United States will not hesitate to use necessary and proportionate force to defend U.S., Coalition, or partner forces engaged in the campaign against ISIS.

Congress has debated Syria-specific and Islamic State-focused authorization for military force proposals intermittently in recent years. In 2013, the Senate Foreign Relations Committee considered and reported a proposed authorization for the use of military force following a chemical weapons attack in the suburbs of Damascus, Syria (S.J.Res. 21). The Senate did not consider the measure further. Since U.S. military action against the Islamic State began in June 2014, starting in Iraq and then spreading to Syria, Congress also has debated the need for enactment of a new IS-specific authorization for use of military force. President Obama asserted that the campaign against the Islamic State in Iraq and Syria was authorized by both the Authorization for Use of Military Force (2001 AUMF; P.L. 107-40; claiming that the Islamic State was a successor organization of Al Qaeda and that elements of Al Qaeda were present in Syria) and Authorization for Use of Military Force Against Iraq Resolution of 2002 (2002 AUMF; P.L. 107-243; claiming authority to defend Iraq from the Islamic State threat).

The challenge of Syria reconstruction aid. U.N. Special Envoy for Syria Staffan de Mistura has said that Syria reconstruction will cost at least $250 billion.6 U.S. officials have said that U.S. funds will not flow to government-held parts of Syria for reconstruction purposes until the Syrian government fulfills the terms of UNSCR 2254 (constitutional reform and U.N.-supervised elections). Moreover, the Trump Administration has stated its intention of using U.S. diplomatic influence to discourage other international assistance to government-controlled Syria. With prospects for political negotiations appearing dim after years of negotiations, Congress may debate how the United States might best assist Syrian civilians in need (most of whom live in areas under Syrian government control) without inadvertently strengthening the Asad government. U.S. nonlethal assistance to communities in opposition-held areas continues, but programs in areas that return to Syrian government control may pose challenging questions for U.S. policymakers.

Select Proposed Syria-Related Legislation

H.R. 4681, No Assistance for Assad Act. Introduced in December 2017 by Representatives Engel, Kinzinger, Royce, and Boyle, the bill calls for reconstruction and stabilization assistance to be provided only to "a democratic Syria" or to areas of Syria not controlled by the Asad government. Reconstruction aid could be provided "directly or indirectly" to areas under Syrian government control only if the President certifies to Congress that the government of Syria (1) has ceased attacks against civilians and civilian infrastructure, (2) is taking steps to release all political prisoners, (3) is taking steps to remove senior officials complicit in human rights abuses, (4) is in the process of organizing free and fair elections, (5) is making progress toward establishing an independent judiciary, (6) is complying with human rights, (7) is taking steps toward fulfilling its commitments under international agreements that regulate the proliferation of chemical and nuclear weapons, (8) has halted the development and deployment of ballistic and cruise missiles, (9) is taking steps to remove government officials complicit in torture, extrajudicial killings, or chemical weapons use, (10) is reforming the military and security services to minimize the role of Iran and Iranian proxies, and (11) is in the process of securing the voluntary return of refugees and internally displaced persons.

By noting restrictions on U.S. aid provided "directly or indirectly," the bill also seeks to limit U.S. funds that could flow into Syria via multilateral institutions and international organizations, including the United Nations, the International Monetary Fund, and the World Bank. Recent appropriations acts have authorized the provision of certain types of U.S. assistance to Syria for stated purposes notwithstanding any other provisions of law, without limits based on territorial control or Syrian government policy. A range of restrictions on U.S. assistance to Syria otherwise remains in place as a result of preconflict U.S. sanctions on the Asad government.

The bill would permit exceptions to the above restrictions on aid to government-held areas for projects intended to meet humanitarian needs (including food, medicine, demining, and education), and projects administered by local organizations to meet the needs of local communities. Such projects would require the President to submit a report to appropriate congressional committees.

H.R. 2810/P.L. 115-91 National Defense Authorization Act (NDAA) for FY2018. The FY2018 NDAA limits and sets terms for the use of funds for the transfer of man-portable air defense systems (MANPADs) to the vetted Syrian opposition, preserves oversight reporting on the Syria train and equip program, and requires new reporting on potential Syria-related agreements with Russia and U.S. strategy in Syria. The act also sets terms and limitations for the use of Syria train and equip program monies for construction projects. As noted above, the act did not extend the underlying authority for the train and equip program, which is currently authorized through December 31, 2018.

S.Res. 116, Condemning the Asad regime for its continued use of chemical weapons against the Syrian people. Following the April 4, 2017, chemical weapons attack in Syria, several members of the Senate Foreign Relations Committee submitted a proposed resolution that, inter alia, would condemn Asad and Russia and call on the United Nations Security Council to take immediate, decisive action in response. The proposed resolution "reiterates that Bashar al-Assad has lost legitimacy as Syria's leader" and "insists that Bashar al-Assad must be held accountable for his war crimes and crimes against humanity."

H.R. 1923. Introduced April 5, 2017: would prohibit the President from using members of the Armed Forces "to carry out offensive combat operations in Syria unless Congress has enacted a specific authorization for such use of members of the Armed Forces."

Caesar Syria Civilian Protection Act of 2017. H.R. 1677, introduced by Representatives Royce and Engel (and others) on March 22, 2017: was referred to the Committees on Foreign Affairs, Financial Services, and the Judiciary. The bill updates and amends legislation (H.R. 5732) passed by the House in the 114th Congress, incorporating provisions from other proposed legislation and appearing to address some concerns expressed by various Syria policy stakeholders. On May 17, it passed the House and was referred to the Senate Committee on Foreign Relations.

As amended, H.R. 1677 would state that "It is the policy of the United States that all diplomatic and coercive economic means should be utilized to compel the government of Bashar al-Assad to immediately halt the wholesale slaughter of the Syrian people and to support an immediate transition to a democratic government in Syria that respects the rule of law, human rights, and peaceful coexistence with its neighbors." The bill would authorize the imposition of certain sanctions by the President and amend current law to require the President to impose other sanctions on individuals he designates as eligible. The bill would require the President to submit an updated report on individuals alleged to be responsible for "serious human rights abuses" in Syria, which the bill would amend current law to define. In defining "serious human rights abuses" and requiring the Administration to report on the responsibility of dozens of named individuals for such abuses, the bill appears to create a dynamic that would make it more difficult for the executive branch to decline to designate Syrian individuals for human rights-based sanctions.

The bill would expand the potential scope of existing U.S. sanctions on Syria by making eligible for sanctions parties engaged in certain transactions with or the provision of support to the government of Syria. Current executive orders impose such sanctions, in some cases. The sanctions authorized in the bill could be imposed on individuals determined by the President to have met designated criteria because of knowing engagement in actions "on or after" the date of enactment. The sanctions would thus be prospective rather than retrospective. The sanctions authorized could be imposed on U.S. nationals and non-nationals. A large number of individuals are already subject to U.S. Syria-related sanctions, and in some cases individuals may already be subject to U.S. sanctions for engaging in transactions with sanctioned individuals, including entities in Russia and Iran that provide military support to the Syrian government.

The bill would require within 90 days a report that assesses the potential effectiveness, risks, and operational requirements of the establishment and maintenance of a no-fly zone over part or all of Syria and the establishment of one or more safe zones in Syria for internally displaced persons or for the facilitation of humanitarian assistance. It would also codify authorization for certain services in support of nongovernmental organizations' activities in Syria.

The bill includes a national security waiver and negotiation or transition scenario-specific waiver authorities for the President. Its provisions would expire after December 31, 2021.

Preventing Destabilization of Iraq and Syria Act of 2017. In January 2017, Senators Rubio and Casey introduced S. 138, known as the Preventing Destabilization of Iraq and Syria Act of 2017. They had previously introduced the bill in December 2016 as S. 3536 (114th Congress), known as the Preventing Destabilization of Iraq and Syria Act of 2016. The bill incorporated many aspects of H.R. 5732 (114th Congress), including the requirement for the imposition of sanctions on the Central Bank of Syria as well as on foreign individuals that provide support for the Syrian government or for the maintenance or expansion of natural gas and petroleum production in Syria. In addition, it would require the imposition of sanctions on Syrians complicit in the blocking of humanitarian aid. The bill also would authorize the President to provide enhanced support for humanitarian activities in Syria, including the provision of food, shelter, water, health care, and medical supplies. It would prohibit the President from imposing sanctions on a foreign financial institution for engaging in a transaction with the Central Bank of Syria for the sale of food, medicine, medical devices, donations intended to relieve human suffering, or nonlethal aid to the people of Syria. It further would prohibit the President from imposing sanctions on internationally recognized humanitarian organizations for engaging in financial transactions related to the provision of humanitarian assistance, or for having incidental contact (in the course of providing humanitarian aid) with individuals under the control of foreign persons subject to sanctions under the act.

Recent Developments


Damascus Area: Siege of Eastern Ghouta

Syrian government forces throughout the conflict have regularly conducted strikes on eastern Ghouta, a rebel stronghold that has been under opposition control since 2012. Eastern Ghouta forms part of the Ghouta oasis, an agricultural area outside Damascus (see Figure 3). Government forces have besieged the area since early 2013, limiting the ability of civilians to flee and restricting deliveries of food, medicine, and fuel.7 The Syrian military has conducted numerous air strikes in the area, and in 2013 carried out a sarin gas attack that killed 1,400 people (see "Chemical Weapons and Disarmament"). Armed groups operating in the area have also launched periodic rocket and mortar attacks on central Damascus. In mid-2017, Eastern Ghouta was declared a "de-escalation area" per the Astana process coordinated by Russia, Iran, and Turkey (see "Cease-fires").

In late 2017, U.N. officials stated that 94% of Syrians in besieged areas of the country live in eastern Ghouta.8 They added that only 100,000 out of an estimated 400,000 residents of eastern Ghouta had received food assistance in 2017. In October 2017, U.N. High Commissioner for Human Rights Zeid Ra'ad Al Hussein called the situation of besieged civilians in eastern Ghouta "an outrage," saying "the deliberate starvation of civilians as a method of warfare constitutes a clear violation of international humanitarian law and may amount to a crime against humanity and/or a war crime."9 In January 2018, Secretary of State Tillerson condemned what he described as "an apparent chlorine gas attack" in eastern Ghouta, stating, "the recent attacks in East Ghouta raise serious concerns that Bashar al-Assad's Syrian regime may be continuing its use of chemical weapons against its own people."10

Figure 3. Syria Areas of Influence

Source: CRS using area of influence data from IHS Conflict Monitor, last revised February 19, 2018. All areas of influence approximate and subject to change. Other sources include U.N. OCHA, Esri, and social media reports.

Notes: U.S. military officials have acknowledged publicly that U.S. forces are operating in select areas of eastern Syria to train, advise, assist, and equip partner forces.

In February 2018, Syrian government forces intensified their attacks on eastern Ghouta in what U.N. officials described as "some of the worst fighting of the entire conflict."11 Humanitarian organizations stated that over 200 civilians were killed during a 48-hour period of shelling by Syrian and Russian forces, and that the number of civilian casualties had risen to over 400 in less than a week.12 U.S. and U.N. officials have compared the attack on eastern Ghouta to the Syrian regime's attack on eastern Aleppo in 2016, noting the "ongoing slaughter of trapped civilians."13

Russian officials described reports of Russian participation in air strikes on eastern Ghouta as "groundless accusations."14 However, Russian Foreign Minister Sergei Lavrov stated that "the experience gained in Aleppo, when an agreement was reached with militants on their organized exodus, can be used in Eastern Ghouta."15 The Independent International Commission of Inquiry on Syria in a 2017 report found that war crimes were committed by all parties during the 2016 battle in east Aleppo.16

Israeli Strikes in Syria

On February 10, Israel struck numerous military sites inside Syria—the largest Israeli strike in Syria since the 1982 Lebanon war.17 According to Israeli sources, the strikes were triggered when an Iranian drone crossed from Syria into Israel and was shot down. Israeli fighter jets then struck the T4 military base in central Syria, from which Israel assessed the drone was launched. Anti-aircraft fire hit an Israeli F-16 participating in the operation, which ultimately crashed inside northern Israel after the pilots ejected.18 Russia, whose personnel have used the T4 base near Palmyra, released a statement warning that, "Creating threats to life and security of Russian service personnel, who are in the Syrian Arab Republic at the invitation of its legitimate government in order to assist the fight against terrorists, is absolutely unacceptable."19 It is unknown whether Russian personnel were present at the base at the time of the Israeli strike.

Following the loss of the F-16, Israel then struck what it described as eight Syrian and four Iranian military targets inside Syria, including SA-5, SA-17 and SA-2 sites and a base outside Damascus belonging to key regime protection units. Syria launched surface-to-air missiles in response to the second round of Israeli strikes.

Israel reportedly has conducted several dozen air strikes inside Syria since 2012, which generally have not drawn an overt Syrian military response. The Israeli government typically does not claim responsibility for these strikes, but has described weapons transfers from Iran to Lebanese Hezbollah as a red line.

Eastern Syria: Clearing and Stabilization Operations, U.S. Strikes on Pro-Syrian Forces

As of early 2018, U.S. and coalition-backed forces continued operations against IS remnants in the Middle Euphrates River valley (MERV), focusing on the eastern province of Deir ez Zor. Coalition officials have noted that despite the Islamic State's loss of territory in Syria, it retains the ability to launch successful surprise offensives and retake ground from Syrian government forces.20 Moreover, some IS fighters have fled west into Syrian government-controlled territory, where coalition officials have stated that they do not intend to operate.21 Coalition officials have stated that "we will remain committed to defeating ISIS in the areas that are currently controlled by our partner forces in Syria, and we would call on the Syrian regime to clear ISIS from those areas that are currently under their control."22

U.S. Forces Strike Pro-Syrian Forces near Deir ez Zor. On February 7, 2018, U.S. forces launched air strikes on pro-Syrian government forces near the town of Khusham, east of the provincial capital of Deir ez Zor and on the largely SDF-controlled northeast bank of the Euphrates River. U.S. military officials said that the strikes were conducted in self-defense following an "unprovoked attack" against SDF headquarters near Khusham, which had been contested by Syrian government forces, the SDF, and the Islamic State in 2017. A statement released by CENTCOM stated that coalition servicemembers in an "advise, assist, and accompany" capacity were colocated with the SDF during the attack, which occurred 8 kilometers east of the Euphrates River de-confliction line.23 The air strikes reportedly killed approximately 100 pro-Syrian-government forces, who were described by Syrian state media as "tribal fighters." Some reports suggested that Russian nationals may have been among those killed in the clashes. Khusham is located near one of Deir ez Zor's largest oilfields, which have been contested by various forces throughout the conflict.

Reports Suggest Russian Nationals Killed in U.S. Strikes

Some reports suggest that Russian nationals may have been among those killed in the U.S. strikes near Khusham.24 The precise number is disputed, ranging from 5 to 100, with up to an additional 200 injured.25 Defense Secretary Mattis stated that during the Khusham operation, U.S. officials were informed by their Russian counterparts that there were no Russian forces in the area.26

Russian officials have generally deflected questions about Russian fatalities, stating that no members of the Russian armed forces were killed, and suggesting that any Russian mercenaries killed in the attack had not coordinated their activities with Moscow. A statement released by the Russian Defense Ministry noted that a progovernment militia unit conducting "surveillance and research activities" had come under coalition attack because it had failed to inform a Russian operational group of its plans to operate in the area.27

Russia has a limited number of ground forces deployed in Syria. Various observers have reported and speculated about the roles played by private military companies employing Russian nationals in Syria and the possible nature of their relationships to Russian government activities.

Stabilization Operarations in Raqqah. Since the defeat of the Islamic State in Raqqah in October 2017, the Raqqah Internal Security Forces (RISF) has worked to provide security and prevent IS fighters from returning to cleared neighborhoods. A majority Arab local force comprised of about 3,000 trained volunteers, the RISF works in parallel with the Raqqah Civilian Council, which provides food and supplies to returning residents.28 However, SDF operations in Raqqah continue to face challenges, including the widespread destruction of basic water and electricity infrastructure and the presence of unexploded ordnance. In late January, a U.N. official stated, "humanitarian partners continue to emphasize that given the high prevalence of landmines, booby traps and unexploded ordnance, Raqqa city is not safe for civilian returns."29

Idlib Province: Struggle for Last Rebel-held Province

Idlib, in Syria's northwest, is the only province that remains fully under the control of armed opposition forces. A variety of armed groups currently operate in Idlib province, including Haya't Tahrir al Sham—the successor to the Al Qaeda-affiliated Nusra Front. Idlib province is also one of a handful of "de-escalation areas" created by the Russian-led Astana Process (see below). However, the May 2017 agreement establishing these areas explicitly allows for states to "continue the fight" against extremist groups, and in December 2017 Russian Foreign Minister Lavrov stated that with the "main battle" against the Islamic State completed, Moscow now viewed the defeat of the Nusra Front as its key objective.30 Russia and the Syrian government have traditionally labeled all groups opposing the Syrian regime as "terrorist," suggesting that military operations in Idlib could ultimately aim to eliminate opposition forces more broadly.

In December 2017, the Syrian government (backed by Russia) launched an intensified assault against Idlib. U.N. officials in January 2018 estimated that over 270,000 Syrians have been displaced since mid-December 2017, as a result of air strikes and fighting in southern Idlib and bordering areas of northern Hamah.31 U.N. officials note that many of the thousands of displaced civilians were previously displaced from Hamah and Aleppo provinces.32

Hay'at Tahrir al Sham

In 2016 the Nusra Front, which had been Al Qaeda's affiliate in Syria, declared a split with AQ and changed its name to Jabhat Fatah al Sham (JFS). Most observers viewed the change as nominal, given the continued presence of Al Qaeda leaders in the group's ranks. In 2017, JFS merged with other groups and changed its name to Haya't Tahrir al Sham (HTS). Since then, observers have disagreed on the extent to which HTS remains under central AQ control.33 Unlike Nusra and JFS, HTS has not been formally designated by the United States as a foreign terrorist organization (FTO).34 However, U.S. officials have stated that, "The core of HTS is Nusra, a designated terrorist [organization]. This designation applies regardless of what name it uses or what groups merge into it."35

Afrin: Turkish Operations Against Syrian Kurds

In January 2018, Turkey and some Syrian rebel groups launched a ground operation and air strikes in the Afrin district of northern Aleppo province, targeting forces from the Syrian Kurdish People's Protection Units (YPG). While the YPG forms a significant part of the Syrian Democratic Forces (SDF) that have been the primary U.S. partner in the counter-IS campaign, U.S. military officials have stated that, "we haven't trained or provided equipment for any of the Kurds that are in the Afrin pocket."36 A Turkish official made a disputed claim in late January that a high-level U.S. official agreed to stop providing U.S. arms to the YPG completely.37

U.S. military officials have described the Turkish operations around Afrin as "not helpful," stating that they could distract from ongoing efforts by coalition and local partners in the Euphrates River valley to clear IS remnants.38 In February, Secretary Mattis acknowledged that some units that had previously operated with the SDF had shifted to Afrin in response to Turkish operations there.39 A Pentagon spokesperson stated that some YPG units had moved to Afrin but said that,

Our relationship with the SDF is the counter-ISIS fight. We cooperate with those units that are working to defeat ISIS. The units that have moved out or moved to Afrin are not U.S.-supported units.40

Media reports in late February also stated that pro-Syrian government forces entered Afrin, reportedly in response to a request by Kurdish forces for assistance in securing the border against Turkish military operations.41 A media unit of Lebanese Hezbollah stated that progovernment militia forces were moving from Aleppo into Afrin.42

It is unclear whether Turkish operations will extend eastward into Manbij, currently held by U.S.-backed SDF forces. Turkish President Recep Tayyip Erdogan has threatened to push east to the frontier with Iraq to remove Kurdish fighters from the entire Turkish-Syrian border—potentially setting up conflict between two U.S. partners' forces.43 In late January, Turkey's foreign minister stated that U.S. forces in the Manbij region should be immediately withdrawn.44

Turkish officials have argued that the SDF's continued presence in Manbij violates a promise made by then-Vice President Joe Biden in 2016 that U.S. support for Kurdish forces would be contingent on their withdrawal to areas east of the Euphrates.45 Secretary Tillerson said on February 16, after meeting with President Erdogan in Ankara, that the United States has not completely fulfilled commitments it made to Turkey on Manbij, and that a bilateral working group would address the issue on a priority basis.46

CENTCOM Commander General Joseph Votel has stated that the United States has no plans to withdraw U.S. troops stationed near Manbij.47 U.S. military officials further stated, "We are urging Turkey to deescalate, exercise caution and avoid any actions that might risk conflict between Turkish and American Forces."48 Turkey has been critical of reports that suggested the United States seeks to create a 30,000-person border force comprised largely of SDF (and by extension Kurdish YPG forces) in northern Syria. U.S. military officials have stated that the intended force "is focused solely on internal security, it is not a border force."49

Political Negotiations

The Geneva Process

Since 2012, the Syrian government and opposition have participated in U.N.-brokered negotiations under the framework of the Geneva Communiqué. Endorsed by both the United States and Russia, the Geneva Communiqué calls for the establishment of a transitional governing body with full executive powers. According to the document, such a government "could include members of the present government and the opposition and other groups and shall be formed on the basis of mutual consent."50 The document does not discuss the future of Asad.

Subsequent negotiations have made little progress, as both sides have adopted differing interpretations of the agreement. The opposition has said that any transitional government must exclude Asad. The Syrian government maintains that Asad was reelected (by referendum) in 2014,51 and notes that the Geneva Communiqué does not explicitly require him to step down. In the Syrian government's view, a transitional government can be achieved by simply expanding the existing government to include members of the opposition. Asad has also stated that a political transition cannot occur until "terrorism" has been defeated, which his government defines broadly to include all armed opposition groups.

As part of the Geneva Process, U.N. Security Council Resolution (UNSCR) 2254, adopted in 2015, endorsed a "road map" for a political settlement in Syria, including the drafting of a new constitution and the administration of U.N.-supervised elections. In December 2017, the U.S. Deputy Representative to the United Nations stated that, "the United States remains committed to resolution 2254 (2015) as the sole legitimate blueprint for a political resolution to this conflict."52

The last round of Geneva talks, facilitated by U.N. Envoy Staffan de Mistura, closed in late January.

The Astana Process

Since January 2017, peace talks hosted by Russia, Iran, and Turkey have convened in the Kazakh capital of Astana. These talks have emerged as a parallel track to the Geneva process, and were the forum through which several "de-escalation areas" were established (see "Cease-fires" below). The United States is not a party to the Astana talks but has attended as an observer delegation. The last round of Astana talks closed on December 22. The next round was scheduled for late February 2018 but was postponed.

Russia has played a leading role in the Astana process, which some have described as an alternate track to the Geneva process. The prospect of Astana superseding Geneva has been strongly opposed by the United States, which views Geneva as the only legitimate forum for Syrian political negotiations. Following the release of the Joint Statement by President Trump and Russian President Putin on November 11, 2017, U.S. officials stated that,

We have started to see signs that the Russians and the regime wanted to draw the political process away from Geneva to a format that might be easier for the regime to manipulate. Today makes clear and the [Joint Statement] makes clear that 2254 and Geneva remains the exclusive platform for the political process.53

Sochi Conference. Despite the November agreement, Russia persisted in its attempts to host, alongside Iran and Turkey, a "Syrian People's Congress" in Sochi, intended to bring together Syrian government and various opposition forces to negotiate a postwar settlement. The conference concluded on January 30, but was boycotted by most Syrian opposition groups and included mainly delegates friendly to the Asad government.54


Syria Southwest Cease-fire Area. In July 2017, the United States, Russia, and Jordan established a cease-fire area in southwestern Syria. The area covers parts of the Syrian provinces of Dar'a, Quneitra, and Sweida, and borders the Golan Heights and northwestern Jordan. On November 8, 2017, the parties signed a memorandum of principles (MOP) further defining the southwest cease-fire area. The United States and Russia later issued a Joint Statement regarding the MOP and the situation in Syria. In a background briefing on the Joint Statement, State Department officials said that the MOP

enshrines the commitment of the U.S., Russia, and Jordan to eliminate the presence of non-Syrian foreign forces. That includes Iranian forces and Iranian-backed militias like Lebanese Hizbollah as well as foreign jihadis working with Jabhat al Nusrah and other extremist groups from the southwest area.55

According to the State Department, this includes a commitment to "remove Iranian-backed forces a defined distance from opposition-held territory." Russia has since described the Iranian presence in Syria as legitimate, and suggested that the southwest cease-fire agreement does not imply the withdrawal of pro-Iranian forces from Syria as a whole. In January, Acting Assistant Secretary of State for Near Eastern Affairs David Satterfield stated that many Iranian and Hezbollah positions remained in place within the cease-fire area.56

Astana De-escalation Areas. As part of the Astana process, Russia, Iran, and Turkey announced in May 2017 the establishment of three "de-escalation areas" in Syria: Idlib province and its surroundings, some parts of northern Homs province, and Eastern Ghouta in the Damascus suburbs. Although the United States is not a party to the Astana Process, U.S. officials have said that they support the establishment of de-escalation areas beyond southwest Syria in principle. While violence has decreased in some of the de-escalation areas, others—notably Eastern Ghouta, which has been besieged by government forces for four years—have seen an increase in Syrian government attacks.

Humanitarian Situation

As of early 2018, 13.1 million people in Syria are in need of humanitarian assistance, out of a total estimated population of 18 million. A third of Syria's population (6.1 million) is internally displaced, and an additional 5.5 million Syrians have fled the country.57

International Humanitarian Funding

Multilateral humanitarian assistance in response to the Syria crisis includes both the Regional Refugee and Resilience Plan (3RP) and the Humanitarian Response Plan (HRP). The 3RP is designed to address the impact of the conflict on Syria's neighbors, and encompasses the Lebanon Crisis Response Plan, the Jordan Response Plan, and country chapters in Turkey, Iraq, and Egypt. It includes a refugee/humanitarian response coordinated by UNHCR and a "resilience" response (stabilization-based development assistance) led by UNDP.58

In parallel to the 3RP, the HRP for Syria is designed to address the crisis inside the country through a focus on humanitarian assistance, civilian protection, and increasing resilience and livelihood opportunities, in part by improving access to basic services. This includes the reconstruction of damaged infrastructure (water, sewage, electricity) as well as the restoration of medical and education facilities and infrastructure for the production of inputs for sectors such as agriculture.59 The 2017 3RP appeal sought $5.6 billion, and the HRP for Syria sought $3.4 billion. By the end of 2017, the two appeals had been funded at approximately 54% and 51%, respectively. The 2018 3RP appeal seeks $4.4 billion, and the 2018 HRP appeal for Syria seeks $3.5 billion.60

For additional details on the humanitarian situation in Syria, see CRS In Focus IF10648, Syria's Humanitarian and Protection Crisis: Current Status, by [author name scrubbed].

U.S. Policy

Administration Syria Policy

On January 17, Secretary of State Rex Tillerson laid out the Trump Administration's policy for U.S. involvement in Syria.61 Tillerson's remarks built upon previous testimony by Acting Assistant Secretary David Satterfield62 and were further elaborated in a briefing by a senior State Department official.63

U.S. Goals for Syria

Secretary Tillerson's stated policy objectives for Syria may raise a number of questions, which Members may consider exploring with the executive branch. According to Secretary Tillerson, "the United States desires five key end states for Syria":

Planned U.S. Steps in Syria

In his remarks Secretary Tillerson emphasized "the United States will maintain a military presence in Syria focused on ensuring ISIS cannot re-emerge." He did not describe the intended size of the planned U.S. presence or indicate benchmarks for evaluating its effectiveness. More broadly, he laid out the steps that the Administration plans to take to bring stability and peace to Syria:

Tillerson emphasized the U.S. commitment to "maintaining an American military presence in Syria until the full and complete defeat of ISIS." However, military officials have reported that IS members have fled to areas controlled by the Syrian government. Members of the anti-IS coalition have stated that it does not intend to operate in areas controlled by the Syrian government.64 This has raised the question of how the coalition intends to fully defeat the Islamic State or prevent its return if it does not plan to operate outside of areas controlled by coalition partner forces.

U.S. Military Presence in Syria

As of December 2017, U.S. officials reported that approximately 2,000 U.S. military personnel were deployed in Syria in support of counter-IS operations.65 These include train and equip program-related activities as well as "advise and assist" operations in support of U.S. partner forces. According to recent oversight reporting, U.S. and coalition forces in Syria have trained more than 12,500 members of vetted Syrian opposition groups, among them more than 11,000 members of the SDF.

Military officials have identified the Special Operations Joint Task Force, Operation Inherent Resolve (SOJTF-OIR) led by Major General James Jarrard as "the primary advise, assist and accompany force in Syria, working closely with the SDF."66 SOJTF-OIR reports to the Combined Joint Task Force-Operation Inherent Resolve (CJTF-OIR), which leads the international coalition to defeat the Islamic State in Iraq and Syria.67 In September 2017, Lieutenant General Paul Funk assumed command of CJTF-OIR.

Evolution of the U.S. Deployment in Syria

A small contingent of 50 U.S. Special Operations Forces (SOF) initially deployed to northern Syria in October 2015 to support operations against the Islamic State. In April 2016, their numbers were increased by 250. In December 2016,

then-Defense Secretary Carter announced that the force management level (FML) for U.S. personnel in Syria would be increased to potentially allow the deployment of up to 500 individuals, including special operations forces trainers,

advisors, and explosive ordnance disposal teams. In March 2017, roughly 300 members of the 11th Marine Expeditionary Unit deployed to Syria, providing heavy artillery support to SDF operations. An additional 100 Army Ranger forces deployed to the city of Manbij in Aleppo province. Until the revised estimate of U.S. personnel in Syria was issued in December 2017, U.S. military officials continued to reiterate that the FML for Syria remained 503, while also acknowledging that FML numbers did not include "temporary forces."

In January 2018, U.S. officials stated that over 98% of the territory once held by the Islamic State in Iraq and Syria had been liberated.68 These developments raised the question of whether the United States had achieved its campaign objectives and, if so, whether U.S. personnel could be withdrawn from the country. However, while noting that "ISIS is collapsing, not only as a physical caliphate, but also in ownership of land," senior military officials have also stated that the Islamic State has "disaggregated" into small groups which are likely to fall back into familiar and/or remote areas of Syria and Iraq.69

In early December, Russia's Defense Ministry stated its view that the mission to defeat the Islamic State had been accomplished.70 In response, U.S. military officials stated,

The war against ISIS is not over; and it's not over in Syria. And although we are shifting our forces and the mission is changing, it's also really important that we ensure that ISIS doesn't rise again. So, we're going to stay there and we're going to help give our diplomats the sure footing that they need to ensure the diplomatic process can go forward.71

Defense Secretary Mattis in late December discussed ongoing coalition operations against ISIS remnants in Iraq and Syria, stating that "what we want to do is drive this down to a point that it can be handled by local authorities [Iraqi Security Forces and the SDF]."72 He added that the role of U.S. military personnel was shifting to a stabilizing role that would include training contractors to clear unexploded ordnance, and protecting U.S. diplomats working inside Syria to manage aid funds for the restoration of basic services.

U.S. military officials have emphasized that the stabilization effort is a key part of the military campaign to defeat the Islamic State. Major General James Jarrard, commander of Special Operations Joint Task Force Operation Inherent Resolve, described a "long process" following the military defeat of the Islamic State. He added that "the stabilization efforts in place to allow the IDPs [internally displaced persons] to return home—that is all part of the military defeat of Daesh [the Arabic acronym for the Islamic State]."73 To the extent that counter-IS operations might be broadly defined to encompass stabilization activities, this could also extend the timeline for U.S. forces to remain in Syria.

De-confliction with Russian Forces

In late 2015, the United States established air safety protocols with Russia to de-conflict air operations over Syria. In 2017, U.S. and Russian ground forces in Syria began to operate in close proximity to one another as part of operations to defeat the Islamic State, requiring additional de-confliction measures. Referencing U.S. de-confliction with Russian forces in areas under IS control, a U.S. military spokesperson stated:'s difficult to link up with someone while in contact with the enemy, and especially in the dark. So it gets even tougher when you have a force that may be something other than friendly—not necessarily an adversary, but something other than friendly—and you don't have great communications with them and you don't have an agreed-upon plan. Well, then—and then you add the enemy there, and it becomes fraught with friction. So we knew we had to have this de-confliction system, and we have now acquired that, at the CJTF headquarters. So now there's two nodes for de-confliction with the Russians. The Air Force—the air component has their node, and we now have a node here at the CJTF headquarters, so we can do that.

I think that this becomes—this -- it becomes almost a daily fact of life. In fact, we probably talked to the Russians, between the air component and my headquarters, we talk to the Russians—somebody's talking to the Russians multiple times a day to de-conflict our operations.74

As U.S. operations in Syria shifted east to the Islamic State's self-declared capital at Raqqah in June 2017, additional de-confliction measures were put in place to keep respective forces and their allies separate as they operated in the middle Euphrates River valley (sometimes shortened to MERV).75 According to Defense Secretary Mattis, the de-confliction line runs along the Euphrates River, with pro-Syrian and Russian forces operating to the south and west and U.S.-backed Syrian Democratic Forces (SDF) operating to the north and east.76 In August, Secretary Mattis acknowledged that the execution of the de-confliction arrangement is complex, stating, "every day, it's more and more work, as we come closer and closer together."77

On September 16, Russian aircraft and Syrian government forces struck an SDF position east of the Euphrates River in Deir ez Zor province.78 Following the strikes, senior coalition and Russian officers held a face-to-face meeting described by a military spokesperson as the first meeting between ground commanders "at the general officer level on both sides."79 They reportedly discussed expanded de-confliction measures aimed at avoiding "inadvertent" fire between the respective sides. On September 25, Syrian forces conducted artillery strikes near SDF positions north of Deir ez Zor. Coalition forces were not in the area at the time.80

As discussed above, a February 2018 incident involving the advance of Syrian government forces from an area under their control on the northeast bank of the Euphrates River east of Deir ez Zor city toward an SDF base to the east where U.S. troops were located resulted in U.S. strikes that reportedly killed more than 100 progovernment personnel. The incident highlights ongoing tensions in eastern Syria where pockets of IS fighters remain and U.S.-backed SDF forces control territory that sits atop valuable oil resources, the Khabour River valley, and strategic areas near the Iraqi border.

U.S. Assistance

U.S. Military Operations in Syria and U.S. Train, Advise, Assist, and Equip Efforts

Authorities and Operations

U.S. strike operations against the Islamic State and Al Qaeda affiliated targets in Syria continue pursuant to the 2001 Authorization for Use of Military Force. As of January 2018, the Department of Defense reported that the cost of military operations in Iraq and Syria against the Islamic State since August 2014 had reached $18.5 billion.

In 2014, Congress created a new authority for the Department of Defense (DOD) to train and equip select Syrians in the FY2015 National Defense Authorization Act (NDAA, Section 1209 of P.L. 113-291, as amended). This authority, as amended by subsequent legislation, enables DOD "to provide assistance, including training, equipment, supplies, stipends, construction of training and associated facilities, and sustainment, to appropriately vetted elements of the Syrian opposition and other appropriately vetted Syrian groups and individuals." Such assistance activities are authorized for select purposes, including supporting U.S. efforts to combat the Islamic State and other terrorist organizations in Syria and promoting the conditions for a negotiated settlement to Syria's civil war.

The FY2017 NDAA (P.L. 114-328) extended the authorization for the program through December 31, 2018, but the FY2018 NDAA (H.R. 2810, P.L. 115-91) did not extend it further. Instead, the FY2018 act requires the President to submit a report describing U.S. strategy in Syria not later than February 1, 2018. Potentially Congress will consider whether or not to extend the authority for the program in the context of its consideration of the FY2019 NDAA and FY2019 foreign assistance and defense appropriations legislation.

Congress has not appropriated funds specifically for the Syria train and equip program since the program's inception. Rather, Congress has authorized the Department of Defense to reprogram funds from global counterterrorism assistance accounts to operations and maintenance accounts to support program activities, with each reprogramming subject to the prior approval of the four congressional defense committees. As of February 2018, more than $2.2 billion has been reprogrammed or requested for the program. (Table 1 provides information about program funding and related requests.) Funds appropriated for the Counter-ISIL Train and Equip Fund (CTEF) account by the FY2017 Defense Appropriations Act (Division C of P.L. 115-31) remain available to fund the program until September 30, 2018, subject to "prior approval" reprogramming procedures. President Trump requested $500 million in FY2018 defense CTEF funds for the program. The FY2018 NDAA authorizes the appropriation of that amount, and pending FY2018 defense appropriations legislation would appropriate requested CTEF amounts.

Table 1. Syria Train and Equip Program: Appropriations Actions and Requests

$, thousands


FY2015 Approved Transfers

FY2016 Approved Transfers

FY2017 Approved Transfers

FY2017 Requests

FY2018 Syria-Specific Request

FY2019 Syria-Specific Request



(O&M FY15)


(CTPF FY15/16)


(CTPF FY16/17)








(CTPF FY15/16)


(CTPF FY16/17)


(CTEF FY17/17)






(CTPF FY15/16)






(CTPF FY15/16)




Net Total







Combined Net Total



Source: Executive branch appropriations requests and reprogramming notifications.

Notes: Counterterrorism Partnerships Fund (CTPF). Counter-Islamic State of Iraq and Syria (ISIS) Train and Equip Fund (CTEF). The authority for the Syria Train and Equip Program requires the Department of Defense to submit prior approval notices to transfer funds into various service and department-wide Operations and Maintenance accounts for program activities. Funds listed were approved for transfer by the required congressional defense and appropriations committees during the fiscal years noted.

a. In 2016, President Obama requested $250 million for the Syria train and equip program for FY2017, and, in March 2017, the Trump Administration requested an additional $180 million in FY2017 funds for the program.

b. The Trump Administration requested $500 million for Syria train and equip program efforts as part of its FY2018 defense appropriations request for the Counter-IS Train and Equip Fund (CTEF).

c. During the period for which a continuing resolution was active for FY2017 defense funding, DOD sought and received committee approval for the reprogramming of $250 million in CTPF funds to O&M accounts. The final FY2017 defense appropriations act did not appropriate CTPF funds, and in August 2017, DOD cancelled prior approval reprogramming request 17-05 and submitted request 17-26 to reimburse O&M accounts for the cancelled funds using CTEF monies. The reimbursed amount was $168 million.

As of December 2017, U.S. officials reported that approximately 2,000 U.S. military personnel were deployed in Syria in support of counter-IS operations, including train and equip program-related activities. U.S. forces operate in Syria for train and equip program purposes as well as to advise and assist U.S. partner forces, whether or not those specific partner forces were trained and/or armed under the train and equip program. Such "advise and assist" activities may be conducted pursuant to the authorities outlined by train and equip program provisions or pursuant to other defense authorities defined in law or asserted by the executive branch. This includes military operations against IS targets conducted pursuant to the 2001 Authorization for Use of Military Force.

The Administration's FY2019 request for Syria train and equip funds envisions the requested funding supporting the procurement of weapons, vehicles, and supplies and the provision of life support and operational sustainment for a 35,000-person Internal Security Force (ISF) and 30,000 person combat force (to include ISF stipends). According to the request, as of early 2018, 10,000 vetted Syrian organization members are receiving Defense Department-funded monthly stipends.

Issues for Congress

Over time, both the purposes and content of the program have evolved. The Obama Administration initially proposed the program in early 2014 as a means to influence the outcome of Syria's civil war, but amended its authorization and appropriations requests to Congress later that year to include and emphasize counterterrorism objectives in the midst of the Islamic State's contemporaneous territorial gains in Syria and Iraq. After an initial iteration of the program designed to recruit, train, and equip new forces failed to produce intended results, the Obama Administration reengineered its approach in October 2015 to emphasize and focus on support of vetted existing forces actively engaged in operations against the Islamic State. This approach has defined the program's implementation since, with U.S. training and equipping efforts focusing on improving the capabilities of the Syrian Democratic Forces (SDF), along with smaller U.S. partner forces based in southeastern Syria.

During congressional consideration of proposed train and equip authorities in 2014, some Members of Congress raised questions about how the executive branch might respond in instances where U.S. personnel or partner forces in Syria came under threat. These debates reflected concern among some Members of Congress that U.S. military personnel inside Syria might come under threat from Syrian military forces or their allies, which could risk confrontation with the Syrian government and/or its state and nonstate partners—including Russia, Iran, and Hezbollah—in the event of U.S. preemption or retaliation.

In recent years, U.S. forces in Syria have participated in military operations in forward areas where contact with various hostile forces has occurred. The Obama Administration stated its intent to defend U.S. personnel and partner forces in Syria, but did not conduct force protection strikes against the Syrian government or its allies. During 2017 and 2018, U.S. military strikes have targeted units of regular and irregular forces aligned with the government of Syria in instances where U.S. forces have determined that those Syrian government-aligned units have posed direct threats to U.S. personnel and/or to U.S. partner forces. U.S. forces also reportedly have returned fire in areas where nonstate actors who may have Turkish support have fired small arms at or near U.S. positions near the northern city of Manbij. In July 2017, the Trump Administration described a series of strikes taken to defend U.S. and partner forces in 2017 as "limited and lawful measures to counter immediate threats to U.S. or partner forces engaged" in the campaign against the Islamic State. Administration officials asserted that U.S. forces derive the authority to protect themselves and their partners from the underlying authorities the executive branch cites for the U.S. military presence in Syria.

The U.S. military expects that the Islamic State organization will be defeated as a coherent military force in Syria in the near term, and DOD officials have requested funding to reshape the content and conduct of U.S. assistance programs and parallel U.S. military operations in Syria in response. In December 2017, a DOD spokesman said that "While the nature of U.S. support to partner forces will adjust as the coalition shifts from major urban combat operations to stabilization tasks, U.S. support will not end until the enduring defeat of ISIS and will be determined by conditions on the ground."81 As noted above, DOD's FY2019 request for train and equip funding in Syria envisions the creation of U.S.-supported security forces in opposition-held areas of northern and eastern Syria with up to 65,000 members. Pending requests may reopen debates in Congress about the proper scope, nature, and limits of ongoing U.S. military operations and training and equipment support.

Evolution in future U.S. support could feature an increased emphasis on counterterrorism and internal security capacity building assistance for U.S. partner forces relative to past efforts to increase military capacity. Such evolution could also result in a reduction in specific types or amounts of support based in response to changing conditions. Specifically, this might entail changes in prevailing patterns of training and/or equipment provision to past partners. The FY2019 request projects more spending on sustainment of partner forces than on weapons and equipment relative to past requests. These types of changes, in turn, could have implications for the security of U.S. partner forces, as well as prompt changes in their domestic political orientation, security, and attitudes toward the United States.

In particular, U.S. assistance to elements of the Syrian Democratic Forces to date has enabled SDF units to operate across large areas of northeastern Syria and deploy relatively formidable military capabilities against their Islamic State adversaries. To the extent that distinct components of the SDF, including Kurdish YPG fighters, also seek to preserve and protect the autonomy and security of Kurdish areas and support distinct political prerogatives, changes in patterns of U.S. assistance might have security and political effects. The empowerment of new groups and individuals as part of efforts to recruit, train, equip, and sustain the Internal Security Force may also have important political and security implications in local areas.

Other Reported U.S. Assistance

Then-Secretary of Defense Chuck Hagel said in a September 2013 hearing before the Senate Foreign Relations Committee that the Obama Administration was taking steps to provide arms to some Syrian rebels under covert action authorities.82 Several press accounts citing unnamed U.S. government sources subsequently described details of reported U.S. and partner nation efforts to that effect.83 From 2014 onward, various anti-Asad forces released videos of their operatives loading and firing what appeared to be U.S.-origin antitank weaponry in Syria.84 Asked in April 2014 about the reported shipments and use of U.S. origin weaponry by Syrian rebels, U.S. National Security Council then-spokeswoman Bernadette Meehan said, "The United States is committed to building the capacity of the moderate opposition, including through the provision of assistance to vetted members of the moderate armed opposition. As we have consistently said, we are not going to detail every single type of our assistance."85 In October 2015, unnamed U.S. officials were cited in press reports that suggested that Russia was actively targeting Syrian opposition groups that had received covert support from the United States.86 In July 2017, press reports citing unnamed U.S. officials stated that the Trump Administration had decided to end a reported program of aid to anti-Asad forces and focus instead on defeating the Islamic State via Defense Department-led train, advise, assist, and equip efforts.87

U.S. Nonlethal Assistance to Syrians and the Syrian Opposition

Authorities and Operations

A broad set of bilateral U.S. sanctions on Syria existed prior to the outbreak of conflict, and some, such as those triggered by Syria's designation as a state sponsor of terrorism, initially had a limiting effect on the delivery of U.S. assistance in the country. At the executive branch's request, Congress has granted the executive branch specific authority to provide nonlethal foreign assistance in Syria for certain purposes notwithstanding other provisions of law, and the executive branch has acted to waive other restrictions imposed by law.88 Outside of the proscribed eligible purposes, U.S. assistance to Syria remains restricted by a series of preexisting provisions of law (including some terrorism-related sanctions provisions).

Prior to the enactment of specific notwithstanding authority by Congress, the President was required to assert emergency and contingency authorities (i.e., Sections 451 and 614 of the Foreign Assistance Act of 1961, as amended) to provide nonlethal assistance to the unarmed Syrian opposition and to communities inside Syria.89 In 2012, the Administration began to use these emergency and contingency authorities to provide food rations and medical supplies to the National Coalition of Revolutionary and Opposition Forces (SOC) and the Turkey-based Syrian Military Council (SMC).

Since then, as directed by specific provisions in appropriations bills, U.S. assistance in Syria has expanded to encompass a range of smaller, local groups and actors, including municipal authorities, local councils, and nongovernmental organizations in opposition-held areas.90 Syrian recipients use U.S. assistance to bolster governance by providing services such as emergency power, sanitation, water, and education services. Other U.S. assistance programs support the maintenance of public safety, rule of law, and the documentation of human rights violations.

Under authorities now in effect, congressional committees of jurisdiction are notified when the Administration intends to obligate funds from designated accounts for "non-lethal assistance for programs to address the needs of civilians affected by conflict in Syria, and for programs that seek to—91

(A) establish governance in Syria that is representative, inclusive, and accountable;

(B) empower women through political and economic programs, and address the psychosocial needs of women and their families in Syria and neighboring countries;

(C) develop and implement political processes that are democratic, transparent, and adhere to the rule of law;

(D) further the legitimacy and viability of the Syrian opposition through cross-border programs;

(E) develop and sustain civil society and independent media in Syria;

(F) promote stability and economic development in Syria;

(G) document, investigate, and prosecute human rights violations in Syria, including through transitional justice programs and support for nongovernmental organizations;

(H) expand the role of women in negotiations to end the violence and in any political transition in Syria;

(I) assist Syrian refugees whose education has been interrupted by the ongoing conflict to complete higher education requirements at universities and other academic institutions in the region, and through distance learning;

(J) assist vulnerable populations in Syria and in neighboring countries;

(K) protect and preserve the cultural identity of the people of Syria as a counterbalance to extremism, particularly those living in neighboring countries and among youth;

(L) protect and preserve cultural heritage sites in Syria, particularly those damaged and destroyed by extremists; and

(M) counter extremism in Syria."

Current law requires the Secretary of State to "take all practicable steps to ensure that mechanisms are in place for the adequate monitoring, oversight, and control of such assistance inside Syria," and requires the Secretary of State to "promptly inform the appropriate congressional committees of each significant instance in which assistance provided pursuant to this subsection has been diverted or destroyed, to include the type and amount of assistance, a description of the incident and parties involved, and an explanation of the response of the Department of State."

Provisions in annual appropriations act that have defined the terms for these programs have required the executive branch to update its comprehensive interagency strategy prior to obligating funds under the authorities.92 All funds obligated pursuant to the authorities have been subject to established congressional notification procedures. These provisions of law authorizing the use of appropriated funds for select purposes notwithstanding other provisions of law have not explicitly prohibited the potential obligation or expenditure of funds in areas of Syria controlled by the Syrian government. As noted above, legislation under consideration in the 115th Congress would place restrictions on the use of U.S. assistance in government-controlled areas unless certain conditions are met (see "Select Proposed Syria-Related Legislation" above).

To implement, coordinate, and monitor cross-border assistance programs, a U.S. Syria Transition Assistance and Response Team (START) operates from Turkey and coordinates U.S. humanitarian and foreign assistance to northern Syria, including assistance to opposition-held areas. In Jordan, the Southern Syria Assistance Platform (SSAP) operates and coordinates comparable U.S. humanitarian and foreign assistance to southern and eastern Syria, including assistance to opposition-held areas. As of January 2018, the Trump Administration also reported that U.S. civilian assistance authorities are present inside areas of northern Syria where DOD-trained and/or equipped local forces are in control.

The State Department requested more than $480 million in FY2016 and FY2017 funding to provide nonlethal support to vetted, moderate armed opposition groups, other opposition actors, and communities in opposition-held areas of Syria. The Trump Administration has requested $191.5 million in Overseas Contingency Operation funding for State Department-administered programs in Syria for FY2018, including $150 million in Economic Support and Development Fund (ESDF)-OCO monies. The Administration did not request Peacekeeping Operations (PKO) funding specifically for Syria—in recent years funds from this account have provided nonlethal assistance to armed and unarmed Syrian opposition elements. The Administration is requesting $130 million in ESDF-OCO for stabilization efforts in nongovernment-controlled areas of Syria in FY2019, out of an overall request of $174.5 million for Syria programs.

Congress appropriated additional funds in the December 2016 continuing resolution to support stabilization in areas liberated from the Islamic State. The Obama Administration reported to congressional appropriators in January 2017 its intended spending plan for these funds, including several hundred million dollars of projected obligations for programs in Syria. Some of these funds have been notified to Congress for obligation since early 2017, but some of these post-IS stabilization monies remain unobligated and available until September 30, 2018.

The House and Senate versions of the FY2018 Foreign Operations Appropriations Act would extend current authorities through FY2018 (Section 7041(j) of Division G of H.R. 3354 and Section 7041(i) of S. 1780). The House version would authorize only the use of Title III/Bilateral Economic Assistance accounts funding for the authorized purposes, whereas the Senate version would authorize the use of ESF, INCLE, NADR, and PKO account funds, consistent with provisions enacted since FY2016.93 Relative to current law and the FY2018 House proposal, the Senate proposal would additionally authorize the use of funds appropriated by the act to "facilitate the return of displaced persons to liberated areas in Syria, including through demining and unexploded ordnance clearance programs."

The Senate version envisions an update of the current interagency strategy as needed, but not as a prior condition to the obligation of funds appropriated by the act. It also would not restate existing monitoring and oversight provisions as preobligation requirements. In parallel, the Senate bill would authorize the use of $500 million from various foreign assistance accounts for a "Relief and Recovery Fund" for aid to "areas liberated or at risk from, or under the control of, the Islamic State of Iraq and Syria, other terrorist organizations, or violent extremist organizations" (§7041(h) of S. 1780). These funds could presumably support stabilization efforts inside Syria, and the appropriations language would not limit their use to nongovernment held areas.

Issues for Congress

Over time, Administration officials have noted that U.S. efforts to deliver and monitor security assistance and other aid inside Syria have been hindered by host nation administrative procedures, border closures, fighting inside Syria, and risks from extremist groups. In the past, some U.S. nonlethal assistance to armed Syrian opposition groups has fallen into the hands of unintended recipients and has led to changes in delivery and oversight mechanisms.94 Infighting among some opposition forces, the empowerment of the Islamic State in Syria, and concerns expressed by other outside actors such as Russia and Turkey have created further complications over time. Although the Islamic State has lost control of border crossings it formerly held, other anti-U.S. extremist groups control some border crossings in northwestern Syria.

Increasingly vocal demands by the Syrian government and its international supporters for an end to cross-border assistance operations may significantly complicate U.S. assistance operations and prompt difficult decisions for U.S. policymakers. This dynamic was evident in Russian objections during late 2017 to the 12-month renewal of the U.N. Security Council mandate for cross-border and cross-line humanitarian operations (Resolution 2393), but it similarly applies to ongoing Syrian and allied rejections of nonhumanitarian assistance operations in opposition held areas.

Depending on the outcome of negotiations regarding de-escalation zones and the potential reassertion by national authorities of political and security control over opposition-held areas, past recipients of U.S. foreign assistance could become politically exposed and subject to persecution. This, in turn, could prompt renewed conflict or population displacement. In general, a negotiated or imposed political solution to the Syria conflict may result in a greater reassertion of sovereignty by the Syrian government and a greater recognition by international actors of that sovereignty. Under these circumstances or in anticipation of this outcome, Congress could revisit fundamental questions about the authorization for, purposes and content of, and volume or terms for U.S. defense and foreign assistance programs in Syria. Ongoing debates about a continued U.S. military presence and U.S. participation in potential reconstruction efforts reflect these issues, illustrating tensions between U.S. concerns about political outcomes and the potential security imperatives of stabilizing conflict-torn areas.

U.S. Humanitarian Assistance

The United States is the largest donor of humanitarian assistance to the Syria crisis, drawing from existing funding from global humanitarian accounts and some reprogrammed funding.95 As of early 2018, total U.S. humanitarian assistance for the Syria crisis since 2011 has reached nearly $7.7 billion.96

In December 2016, the Further Continuing and Security Assistance Appropriations Act, 2017 (P.L. 114-254), made funds available at FY2016 levels primarily through the Migration and Refugee Assistance (MRA) and International Disaster Assistance (IDA) accounts. Division B of the act provided an additional $916 million in FY2017 supplemental funding through MRA and IDA for the humanitarian response in Iraq and Syria. The Consolidated Appropriations Act, 2017 (P.L. 115-31) provides funding to several global humanitarian accounts, including $3.058 billion in MRA and $3.811 billion in IDA, some of which will be used to respond to the Iraq-Syria crises.

The Trump Administration's FY2018 appropriations request seeks more than $2.5 billion in enduring and OCO funding for the IDA account, some of which would be used to respond to the Iraq and Syria crises. The Administration also seeks more than $2.7 billion for the MRA account, including $1.2 billion for MRA-funded programs in the Near East region. The FY2019 request seeks $1.78 billion in IDA-OCO funding and $2.35 billion for MRA overseas operations—these totals include funds for responses to the Iraq and Syria crises.

Chemical Weapons and Disarmament97

A major policy concern of the United States has been the use of chemical weapons in Syria during the ongoing civil war. There have been dozens of reports of chemical weapons use in the Syrian conflict over the past several years. A February 5, 2018 State Department press statement said that chlorine gas had been used six times by the Syrian regime against civilians in the past 30 days.98 Two major incidents of reported nerve agent (sarin) use by the Syrian military were in April 2017 and August 2013. The reported use of the nerve agent sarin by aerial bombardment on April 4, 2017, in the town of Khan Sheikhoun in rebel-held Idlib province killed an estimated 80 to 100 people and returned the issue of chemical weapons in Syria to center stage. Secretary of State Tillerson said that the U.S. government had a "very high level of confidence" that the Syrian air force had used the nerve agent sarin in three recent attacks—on March 25, March 30, and April 4.99 In testimony to the Senate Select Committee on Intelligence on May 11, Director of National Intelligence Daniel Coats said that Syria was probably "willing and able" to use chemical weapons again.100 The U.S. Ambassador to the OPCW, Kenneth Ward, said on October 10 that "Syria has produced and continues to possess stocks of nerve agent and its immediate precursor chemicals."101

On April 6, the United States responded with missile strikes against Al Shayrat air base, which Pentagon officials stated is used to store chemical weapons.102 President Trump said that "It is in the vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons."103 Secretary of State Rex Tillerson also said the U.S. strike was aimed at reestablishing the norm against chemical weapons use:

As Assad has continued to use chemical weapons in these attacks with no response—no response from the international community—that he, in effect, is normalizing the use of chemical weapons, which may then be adopted by others. So it's important that some action be taken on behalf of the international community to make clear that the use of chemical weapons continues to be a violation of international norms.104

The World Health Organization said on April 5 that it was alarmed by the use of chemicals in Syria the previous day.105 The Turkish Ministry of Health said on April 6 that it had assessed that victims of the attack were exposed to sarin.106 The Organization for the Prohibition of Chemical Weapons (OPCW) began a fact-finding mission on April 5 to investigate the event, and its inspectors collected samples which were sent to predesignated laboratories. The OPCW Director General said on April 19 that four of its laboratories had "incontrovertible" evidence that sarin or a sarin-like agent was used on April 4:

The bio-medical samples collected from three victims during their autopsy were analysed at two OPCW designated laboratories. The results of the analysis indicate that the victims were exposed to Sarin or a Sarin-like substance. Bio-medical samples from seven individuals undergoing treatment at hospitals were also analysed in two other OPCW designated laboratories. Similarly, the results of these analyses indicate exposure to Sarin or a Sarin-like substance.107

The largest-scale use of chemical weapons in Syria to date was an August 21, 2013, nerve gas attack, which the U.S. government estimated killed more than 1,400 people.108 In August 2013, the Obama Administration had threatened military action against Syria in response to alleged nerve gas attacks by Syrian government forces. As part of a diplomatic solution to the crisis based on a U.S.-Russian joint proposal, the Obama Administration withdrew the threat of military force and Syria agreed to give up its chemical weapons and join the Chemical Weapons Convention (CWC). U.N. Security Council Resolution 2118 (2013) further mandated that Syria give up all its chemical weapons under Chapter VII provisions of the U.N. Charter.109

After joining the CWC, Syria declared that it possessed 1,308 metric tons of chemical warfare agents and precursor chemicals, including several hundred metric tons of the nerve agents sarin and VX, as well as mustard agent in ready-to-use form. The nerve agents were stored as two separate components that are combined before use, called precursor chemicals, a form that facilitated removal and destruction efforts. The international community oversaw the removal and destruction of the declared chemical weapons agents from Syria, and, as of January 4, 2016, all declared Category 1 and 2 chemicals had been neutralized.110

Verification of the destruction of chemical weapons facilities is still underway. As of September 2017, the OPCW had verified that 25 of the 27 declared chemical weapons production facilities (CWPFs) had been destroyed. The poor security situation had prevented the inspection of the two remaining stationary above-ground facilities.111 For years, the United States, the OPCW Director General, and other governments have raised questions over whether Syria declared all of its chemical weapons stocks and facilities. Press reports, nongovernment experts, and U.S. officials have said that the Asad regime used undeclared stocks of nerve agent in the April 4 attack in violation of its commitments under the CWC.112 The Organization for the Prohibition of Chemical Weapons (OPCW) has not been able to verify the completeness of the declaration, part of Syria's obligations under the CWC. The OPCW's Declaration Assessment Team (DAT) continues to investigate "gaps, inconsistencies and discrepancies" through interviews and lab analysis of samples from site visits, but the cooperation of the Syrian government has been limited and little progress has been made according to OPCW Executive Council reports.113

Since the August 2013 attack, reports of chemical weapons use in Syria have consisted primarily of accusations of chlorine use in barrel bombs until the alleged sarin use in the spring of 2017.114 Reports of the use of chlorine gas as a chemical weapon began to surface in April 2014. The OPCW established a fact-finding mission to investigate these allegations. The use of chlorine as a weapon is banned under the Chemical Weapons Convention. Several governments—including the governments of Syria and the United States—have submitted allegations of chemical attacks to the U.N. Secretary-General and/or the OPCW.115 The United States, the United Nations,116 and others have assessed that the Syrian government has used chemical weapons repeatedly against opposition forces and civilians in the country. Expert teams affiliated with the U.N.-OPCW Joint Mission to Investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic and the OPCW Fact-Finding Mission in Syria have investigated some of these allegations and have found evidence that in some cases confirms and in others suggests that chemical weapons and/or toxic chemicals have been used in attacks by the Syrian regime and by the Islamic State. Syrian civilians, opposition fighters, and military personnel have been targeted in alleged attacks.117

Earlier U.N. and OPCW investigations had not been tasked with assigning responsibility for alleged attacks but with identifying whether chemical weapons were used. However, on August 7, 2015, the U.N. Security Council unanimously adopted Resolution 2235, which established a new OPCW-U.N. Joint Investigative Mechanism (JIM) tasked with identifying "to the greatest extent feasible" those responsible for or involved in chemical attacks identified by the OPCW fact-finding mission.118 In September 2015, the United Nations Security Council adopted the Secretary-General's proposal for the establishment of the OPCW-U.N. JIM, and the Secretary-General appointed Virginia Gamba of Argentina to head the independent three-member panel that leads the JIM.

While Resolution 2235 empowers the JIM to have access anywhere in Syria, the JIM's mission has been complicated by the security situation on the ground. The JIM initially investigated nine attacks alleged to have occurred between April 2014 and August 2015. Of these, three cases lacked sufficient evidence to draw conclusions, three cases require further investigation, and three cases were concluded. Eight of the cases involved chlorine-filled barrel bombs. The JIM reports attributed four cases of chemical weapons use.119 According to the October 2016 report

The Security Council extended the mandate of the JIM through November 2017 despite initial objections by Russia, who argues for a wider regional mandate.121 The JIM's mandate remains limited to investigating alleged incidents of chemical weapons use in Syria, but will also include outreach to the UNSC's nonproliferation committee and neighboring states regarding nonstate use of chemical weapons. The United States has worked to extend the JIM, in order to "send a clear message that the use of chemical weapons will not be tolerated."122 The JIM's mandate was not renewed due to Russia's objections. In the meantime, the OPCW and the Fact-Finding Mission continue to investigate instances of use although without attribution. In January 2018, the French government gathered 30 countries in Paris to announce a new effort, the "International Partnership against Impunity for the Use of Chemical Weapons," to raise awareness of this issue and bolster international pressure on Syria.123 U.S. Secretary of State Rex Tillerson attended.

The Syrian government continues to deny categorically that it has used chemical weapons or toxic chemicals, while accusing opposition forces of doing so and calling into question the methods and results of some investigations into alleged chemical attacks.124 The Russian Federation supports the Syrian position. The U.N. representatives of the United States, France, and the United Kingdom continue to assert that the Syrian government has been conducting chemical attacks. An effort in February 2017 to pass a Security Council Resolution that would sanction Syria failed to get the votes of Russia or China.125 The latest incidence of sarin use on April 4 elevated these issues again to the U.N. Security Council, where Russia defends the Syrian stance. The United States, United Kingdom, and France proposed a U.N. Security Council Resolution in support of a U.N. investigation into who was responsible for the April 4 attack, but this resolution was vetoed by Russia. Nevertheless, the U.N. and OPCW mechanisms already in place from past Security Council resolutions, the Fact Finding Mission (FFM) and the Joint Investigative Mechanism (JIM), investigated the April 4 attack. The FFM concluded that the April 4 attack used sarin. Another U.N. body, the Independent International Commission of Inquiry on the Syrian Arab Republic, issued a report attributing sarin use on April 4 to the Syrian military.

Additional press reports have reported on possible use of mustard gas in Syria and Iraq by IS fighters.126 The OPCW's chief has said that the Islamic State has produced and used sulfur mustard in northern Iraq and Syria.127 U.S. forces struck Islamic State sites in Iraq believed to be associated with chemical weapons production in September 2016, and a multilateral effort removed chemical weapons precursors from Libya in August 2016 after Islamic State affiliate forces threatened the area where the materials had been stored in that country. The Pentagon has said that U.S. troops fighting in Iraq are expected to continue to face weaponized mustard gas attacks by the Islamic State.128 April 2017 press reports said that the Islamic State had used chemical weapons against Iraqi forces in Mosul.129


Over the coming year, policymakers will continue to confront questions regarding U.S. priorities in Syria, as well as regarding the implementation of Administration policy objectives. The Administration has stated that U.S. forces will remain in Syria to prevent the reemergence of the Islamic State, but has not publicly identified benchmarks for their withdrawal. Some Members have questioned whether a sustained U.S. presence in Syria is covered under existing authorities and emphasized the need for a new AUMF.

Defense Secretary Mattis has described Syria as "one of the most complex battlefields you could ever imagine."130 At present, U.S. operations in Syria must account for both the Syrian government (which continues to consolidate control on the ground) and the wide range of external forces which maintain a physical or operational presence in Syria, including Russia, Iran, Lebanese Hezbollah, Turkey, and at times Israel. The rapid escalation of tensions between Syria and Israel in February 2018 highlighted the potential for the outbreak of conflict in the area. In addition, reports that U.S. air strikes in defense of local partner forces may have killed Russian contract soldiers further underscore the risks of unintended escalation.

The success of U.S. and coalition operations in Syria also appears to have eroded the cooperation among regional states that had stemmed from their shared interest in eradicating the Islamic State. Ongoing U.S. support for SDF forces following the Islamic State's defeat in Raqqah has reinvigorated Turkish objections to U.S. policy, and subsequent Turkish operations targeting Kurdish forces in Afrin have been described by U.S. officials as an unhelpful distraction from SDF stabilization operations in northern Syria. The SDF is a key beneficiary of the Syria Train and Equip program, whose program authority was extended by the FY2017 NDAA through the end of 2018. Members may extend and/or adjust the program's authorities during consideration of the FY2019 NDAA and the FY2019 foreign assistance and defense appropriations legislation.

Policymakers may also debate whether and how the United States should be involved in the reconstruction of Syria, the cost of which has been publicly estimated at between $200 billion and $300 billion. The Administration has described stabilization as a key element in preventing the resurgence of the Islamic State in Syria, but remains reluctant to contribute to the reconstruction of Syria absent a political settlement to the conflict that includes a transition away from Asad family rule.

Appendix. Conflict Synopsis

2011: Protests Emerge. In March 2011, protests broke out in the southern province of Dar'a. The unrest was sparked by the arrest of a group of school children, but reflected long-standing political and socioeconomic grievances. Largely peaceful protesters called for political and economic reforms rather than the removal of the Asad government. At the same time, a small armed element was also present within some of the protests. As security forces responded with mass arrests and occasionally opened fire on demonstrators, protests became larger and spread to other towns and provinces.

The opposition movement eventually coalesced into two umbrella groups—one political, one armed—and both based primarily in exile. Political groups merged to form the Syrian National Council (SNC), although members struggled to establish trust and develop shared goals. A small number of junior military defectors formed the Free Syrian Army (FSA), which claimed leadership over the armed opposition but whose authority was generally unrecognized by local armed groups. Ongoing violence, primarily but not exclusively on the part of the Syrian government, prompted President Obama in August 2011 to call for Syrian President Asad to step aside. Meanwhile, Al Qaeda's affiliate in Iraq tasked some of its members to commence operations in Syria under the banner of a new group known as Jabhat al Nusra (aka the Nusra Front). In December 2011, the first Nusra Front suicide attacks hit government buildings in downtown Damascus.

2012: Insurgency. In 2012, the conflict became increasingly violent, as the government began to use artillery and fixed wing aircraft against opposition targets. Extremist attacks became more frequent—between November 2011 and December 2012, the Nusra Front claimed responsibility for nearly 600 attacks in Syria, ranging from more than 40 suicide attacks to small arms and improvised explosive device operations.131 In February 2012, the United States closed its embassy in Damascus, citing security concerns. Local armed groups began to seize pockets of territory around the country, primarily in rural areas. A July bombing in downtown Damascus killed several senior regime officials, including the then-Minister of Defense. Concerns about regime tactics became more acute, and President Obama in August declared that

We have been very clear to the Assad regime, but also to other players on the ground, that a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized.... We have communicated in no uncertain terms with every player in the region that that's a red line for us and that there would be enormous consequences if we start seeing movement on the chemical weapons front or the use of chemical weapons.132

The international community also increased efforts to seek a negotiated solution to the conflict. In June, the United States and Russia signed the Geneva Communiqué, which called for the establishment of a transitional governing body with full executive powers.133 The document, which became the basis of future negotiations between the government and the opposition, did not clarify the role of Asad in any future government. Meanwhile, Syria's political opposition remained divided and in flux. In November, the SNC became part of a larger umbrella group known as the National Coalition of Syrian Revolutionary and Opposition Forces (aka the Syrian Opposition Coalition, SOC), a move which some described as an effort to dilute the influence of Islamist members.

2013: Proxy War and Chemical Weapons. In March 2013, rebels seized the city of Raqqah, which became the first provincial capital to fall out of government control. A series of other opposition victories in the area led the government to effectively concede control of Syria's rural northeast to the opposition. At the same time, the Asad government received military and intelligence support from Iran and Lebanese Hezbollah, as well as political backing from Russia. In turn, the United States, Turkey, and some European and Arab Gulf states increased their support to the Syrian opposition—each prioritizing their own interests and at times working at cross purposes.

In April, the United Kingdom and France reported to the United Nations that there was evidence that the Syrian government had used chemical weapons (CW) on multiple occasions since December 2012.134 In August, the United States attributed a large-scale CW attack on the Damascus suburb of Ghouta to the Syrian government.135 President Obama requested congressional approval of a limited authorization for the use of military force to respond.136 The following month, Russia negotiated an agreement for the Syrian government to dispose of its CW stockpiles and destroy associated facilities in exchange for staving off a U.S. military response.

2014: Caliphate and Operation Inherent Resolve (OIR). In February 2014, Al Qaeda formally disavowed the Islamic State because of the group's interference in Syria and its demands that the Nusra Front recognize IS leadership. After the Nusra Front and other opposition groups forced IS fighters from some areas of northwestern Syria, IS fighters seized vast stretches of territory in central and northeast Syria from local armed groups and in June declared the establishment of a caliphate spanning areas of both Syria and Iraq. Thousands of foreign fighters traveled to Syria and Iraq to join the Islamic State.

In August, the United States began air strikes in neighboring Iraq to stop the group's territorial advance and reduce the threat to U.S. personnel in Iraq. U.S. forces also airdropped humanitarian supplies to members of Iraq's Yazidi religious minority group trapped on Mount Sinjar. In September, the United States expanded air strikes to Syria, with the goal of preventing the Islamic State from using Syria as a base for its operations in Iraq. A subsequent air campaign to lift the IS siege on the Syrian Kurdish town of Kobane brought the United States into partnership with the Kurdish People's Protection Units (YPG), which U.S. officials have come to view as among the United States' most effective partners in the anti-IS campaign. In September 2014, Congress authorized the Administration to begin a train and equip program for select Syrian forces.137 On October 17, 2014, the Defense Department established Combined Joint Task Force-Operation Inherent Resolve (CJTF-OIR) to "formalize ongoing military actions against the rising threat posed by ISIS in Iraq and Syria."

2015: Train & Equip Begins, Russia Enters the Fray. In 2015, the Syrian government faced a number of additional territorial losses. Opposition forces captured the provincial capital of Idlib in northwestern Syria and surrounding areas with the support of Al Qaeda-linked fighters. Islamic State fighters seized territory in central Homs province, and Kurdish fighters expanded their control over areas along the Turkish border. In May, the United States began training the first batch of recruits for the Syria Train and Equip Program. The program was designed to build a local force capable of fighting the Islamic State, protecting opposition-held areas, and "promoting the conditions for a negotiated settlement to end the conflict in Syria."

Over the summer of 2015, Russia began a gradual buildup of Russian personnel, combat aircraft, and military equipment inside Syria, and began air strikes in September. The following month, the United States and Russia signed a memorandum of understanding to establish a safety-of-flight protocol for aircraft operating in the same airspace. Also in October, challenges in implementation led the Administration to modify the Syria Train and Equip program to focus on equipping existing units commanded by vetted leaders. Kurdish YPG forces that had received U.S. support in operations at Kobane merged with a small number of non-Kurdish groups to form the Syrian Democratic Forces (SDF), which began to receive U.S. support.

2016: Failed Cessation of Hostilities, Regime Retakes Aleppo. In 2016, the United States sought to step up diplomatic cooperation with Russia to achieve a reduction in violence. The two countries twice attempted to implement a joint diplomatic initiative for a cessation of hostilities (CoH) between progovernment and opposition forces, yet both initiatives were widely considered unsuccessful. In contrast, the U.S.-led campaign against the Islamic State retook significant territory from the group, severing much of the group's access to the Turkish border—a key supply and foreign fighter transit route. However, the heavy participation of Syrian Kurdish fighters in counter-IS operations triggered Turkish opposition, and in August Turkish forces crossed the Syrian border into the town of Jarabulus, in an operation described by Turkish officials as aimed at neutralizing threats posed by both the Islamic State and Kurdish fighters. Meanwhile, Syrian and Russian forces—backed by Hezbollah, foreign Shia militias, and Iranian forces—increased the intensity of attacks on rebel-held eastern Aleppo, resulting in thousands of deaths. In December 2016, the Syrian government recaptured eastern Aleppo from opposition forces, and Russia and Turkey reached agreement on a proposed cease-fire to be followed by negotiations (see "The Astana Process").

2017: U.S. Strikes Syrian Forces, Coalition-Backed Forces Retake Raqqah. On April 4, Syrian aircraft operating in rebel-held Idlib province conducted several air strikes using what U.S. officials assessed to be a chemical nerve agent.138 The strikes killed roughly 80 to 100 people in the town of Khan Sheikhoun (see map, Figure 3). On April 6, the United States fired 59 Tomahawk missiles at Al Shayrat airfield in Homs province, from which U.S. intelligence sources had concluded the Khan Sheikhoun attack was launched. A Defense Department assessment stated that the U.S. strikes resulted in the damage or destruction of fuel and ammunition sites, air defense capabilities, and about 20 Syrian aircraft.139 In a series of incidents in May and June, U.S. forces carried out defensive strikes against Syrian government and allied forces deemed to be threatening U.S. forces and U.S. partners in Syria.

In June 2017, SDF forces began operations to retake the city of Raqqah, the self-declared capital of the Islamic State. On October 20, 2017, the SDF formally announced the recapture of the city.

Author Contact Information

[author name scrubbed], Coordinator, Analyst in Middle Eastern Affairs ([email address scrubbed], [phone number scrubbed])
[author name scrubbed], Specialist in Middle Eastern Affairs ([email address scrubbed], [phone number scrubbed])
[author name scrubbed], Specialist in Nonproliferation ([email address scrubbed], [phone number scrubbed])



Senate Foreign Relations Committee Hearing on U.S. Policy in Syria After ISIS, January 11, 2018.


Rex Tillerson, "Remarks on the Way Forward for the United States Regarding Syria," Hoover Institute at Stanford University, January 17, 2018.


Senate Foreign Relations Committee Hearing on U.S. Policy in Syria After ISIS, January 11, 2018.


Prepared by Matthew Weed, Specialist in Foreign Policy Legislation.


The letter says the strikes were intended "to degrade the Syrian military's ability to conduct further chemical weapons attacks and to dissuade the Syrian regime from using or proliferating chemical weapons, thereby promoting the stability of the region and averting a worsening of the region's current humanitarian catastrophe."


Security Council Briefing on the Situation in Syria, Special Envoy Staffan de Mistura, November 27, 2017.


Amnesty International, "'Left to die under siege': War crimes and human rights abuses in Eastern Ghouta, Syria," August 12, 2015.


Statement to the Security Council on the humanitarian situation in Syria by Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator, Mark Lowcock, November 29, 2017.


United Nations High Commission for Human Rights, "Syria: Suffering of civilians in Eastern Ghouta 'an outrage' – Zeid," October 27, 2017.


Secretary Rex Tillerson, "Remarks on Russia's Responsibility for the Ongoing Use of Chemical Weapons in Syria," January 23, 2018.


Statement attributed to Ali Al-Za'tari, UN Resident and Humanitarian Coordinator in Syria, on the immediate need for a cessation of hostilities to protect and assist civilians, February 12, 2018.


Syrian Observatory for Human Rights (SOHR), "The number of people killed by the regime and its allies within 48 hours in the besieged Ghouta exceeds the death toll of the civilian casualties in a whole month of shelling escalation," February 20, 2018; SOHR, "19 Casualties in renewed shelling and as a result of extracting more bodies from the rubble of the destruction raise the number of casualties to about 440," February 23, 2018.


State Department Press Briefing, February 20, 2018.


"Russia denies role in deadly air strikes on Syria's Eastern Ghouta," Agence France Presse, February 21, 2018.


"Russia calls on West to use its sway to discipline Jabhat al-Nusra," TASS, February 19, 2018.


Report of the Independent International Commission of Inquiry on the Syrian Arab Republic, A/HRC/34/64, February 2, 2017.


"Israeli Air Force General: Syria Strike Is the Most Substantial Since 1982," Haaretz, February 10, 2018.


"Israel carries out 'large-scale attack' in Syria after Israeli jet crashes under antiaircraft fire," Washington Post, February 10, 2018.


Russian Ministry of Foreign Affairs, "Press release on Israeli air strikes in Syria," February 10, 2018.


Department Of Defense Press Briefing By Maj. Gen. Gedney Via Teleconference, December 27, 2017.






"Unprovoked attack by Syrian pro-regime forces prompts Coalition defensive strikes," CENTCOM Release # 20180208-01, February 8, 2018.


"Dozens of Russians Are Believed Killed in U.S.-Backed Syria Attack," New York Times, February 13, 2018.


"Russian toll in Syria battle was 300 killed and wounded: sources," Reuters, February 16, 2018.


Media Availability with Secretary Mattis, February 8, 2018.


"US seizing economic assets in Syria instead of fighting IS — top brass," TASS Russian News Agency, February 8, 2018.


Department of Defense Press Briefing by Colonel Dillon via Teleconference From Kuwait, December 19, 2017.


Assistant-Secretary-General for Humanitarian Affairs and Deputy Emergency Relief Coordinator, Ms. Ursula Mueller, Statement to the Security Council on Syria, January 30, 2018.


"Russia's Lavrov: main part of battle with Islamic State in Syria is over – RIA," Reuters, December 27, 2017.


Assistant-Secretary-General for Humanitarian Affairs and Deputy Emergency Relief Coordinator, Ms. Ursula Mueller, Statement to the Security Council on Syria, January 30, 2018.


"Syria: Zeid condemns upsurge in civilian casualties in Eastern Ghouta and Idlib," U.N. Office of the High Commissioner for Human Rights, January 10, 2018.


See, for example, Daniel Byman, "An al-Qaeda Setback in Syria?" Lawfare, December 6, 2017.


JFS was designated an alias of the Nusra Front in November 2016 (; but to date HTS has not.



Department of Defense Press Briefing by Pentagon Chief Spokesperson Dana W. White and Joint Staff Director Lt. Gen. Kenneth F. McKenzie Jr. in the Pentagon Briefing Room, January 25, 2018.


Tuvan Gumrukcu, "U.S. to end weapons support for Syrian Kurdish YPG, Turkey says," Reuters, January 27, 2018.




On the Record Press Gaggle by Secretary James N. Mattis, February 11, 2018.


"US: No support to YPG units that go to Afrin," Hurriyet Daily News, February 6, 2018.


"Syria war: Pro-government forces enter Kurdish-held Afrin," BBC, February 20, 2018.


"Pro-Syrian government fighters start to enter Afrin – Hezbollah media unit," Reuters, February 20, 2018.


"Turkish operations in Syria to reach up to Manbij and Iraqi border: Erdoğan," Hurriyet Daily News, January 26, 2018.


"Turkey says U.S. needs to withdraw from Syria's Manbij region immediately," Reuters, January 27, 2018.


Wladimir Van Wilgenburg, "Turkey Closes in on U.S. Allies in Syria–This Could Get Really Messy," Daily Beast, January 24, 2018.


Remarks by Secretary Tillerson, Press Availability with Turkish Foreign Minister Mevlut Cavusoglu, Ankara, Turkey, February 16, 2018.


"US general: US troops won't withdraw from Syrian city of Manbij," CNN, January 29, 2018.


Col. Rob Manning III, Director of Defense Press Operations, responses to Taken Questions from January 25, 2018 press briefing.


Department of Defense Press Briefing by Pentagon Chief Spokesperson Dana W. White and Joint Staff Director Lt. Gen. Kenneth F. McKenzie Jr. in the Pentagon Briefing Room, January 25, 2018.


Action Group for Syria, Final Communiqué, June 30, 2012,


"Syrian President Bashar al-Assad Wins Third Term," BBC, June 5, 2014.


Ambassador Michele J. Sison, U.S. Deputy Permanent Representative to the United Nations, "Explanation of Vote following the Adoption of UN Security Council Resolution 2393 on Syria," December 19, 2017.


Background Briefing on the Joint Statement by the President of the United States and the President of the Russian Federation on Syria, November 11, 2017.


"Syrian Peace Talks in Russia; 1,500 Delegates, Mostly Pro-Assad," New York Times, January 30, 2018.


Background Briefing on the Joint Statement by the President of the United States and the President of the Russian Federation on Syria, November 11, 2017.


Senate Foreign Relations Committee, hearing on U.S. Policy in Syria After ISIS, Acting Assistant Secretary of State for Near Eastern Affairs David Satterfield, January 11, 2018.


United Nations Office for the Coordination of Humanitarian Affairs (UNOCHA): Syria Arab Republic.


For additional details, see UNDP and UNHCR, 3RP Regional Refugee & Resilience Plan 2017 – 2018: In Response to the Syria Crisis: Regional Strategic Overview, December 5, 2016.


For additional details, see UNOCHA, 2017 Syrian Arab Republic Humanitarian Response Plan: January - December 2017.


Regional Strategic Overview, Regional Refugee & Resilience Plan (3RP) 2018-2019; Syria Humanitarian Response Plan 2018, Financial Tracking Service.


Rex Tillerson, "Remarks on the Way Forward for the United States Regarding Syria," Hoover Institute at Stanford University, January 17, 2018.


Testimony Before the Senate Foreign Relations Committee, "U.S. Policy Toward Syria Post-ISIS," Statement of David. M. Satterfield, January 11, 2018.


Briefing on Syria, Senior State Department Official via Teleconference, January 19, 2018.


Department Of Defense Press Briefing By Maj. Gen. Gedney Via Teleconference, December 27, 2017.


"Pentagon Announces Troop Levels in Iraq, Syria," DoD News, December 6, 2017.


Department of Defense Press Briefing by General Jarrard via teleconference from Baghdad, Iraq, October 31, 2017.


See for an organization chart.


"Defeat-ISIS Coalition Reflects on 2017, Looks Forward to 2018,", January 1, 2018.


Department of Defense Press Briefing by Brigadier General Andrew A. Croft, deputy commander, Air, Combined Joint Forces Land Component Commander-Operation Inherent Resolve, November 7, 2017.


"Russian military: mission accomplished, Islamic State defeated in Syria," Reuters, December 7, 2017.


Department of Defense Press Briefing by Pentagon Chief Spokesperson Dana W. White and David L. Norquist, Undersecretary Of Defense, Comptroller, December 7, 2017.


Press Gaggle with Secretary Mattis, December 29, 2017.


Department of Defense Press Briefing by Major General James Jarrard, commander, Special Operations Joint Task Force-Operation Inherent Resolve, October 31, 2017.


Department of Defense Press Briefing by General Townsend via teleconference from Baghdad, August 31, 2017.


Department of Defense Press Briefing by General Townsend via teleconference from Baghdad, August 31, 2017.


Media Availability with Secretary of Defense Jim Mattis; Brett McGurk, Special Presidential Envoy for the Global Coalition to Counter the Islamic State of Iraq and the Levant, August 21, 2017.




"Jets strike U.S.-backed forces in eastern Syria," Reuters, September 16, 2017.


Department of Defense Press Briefing by Colonel Dillon via teleconference from Baghdad, September 21, 2017.


Department of Defense Press Briefing by Colonel Dillon via teleconference from Baghdad, September 28, 2017.


Pentagon Spokesman Eric Pahon, quoted in Ryan Browne, Barbara Starr and Jamie Crawford, "Pentagon: US committed to Syria until ISIS areas stabilized," CNN, December 5, 2017.


Secretary Hagel said, "it was June of this year that the president made the decision to support lethal assistance to the opposition. As you all know, we have been very supportive with hundreds of millions of dollars of nonlethal assistance. The vetting process that Secretary Kerry noted has been significant, but—I'll ask General Dempsey if he wants to add anything—but we, the Department of Defense, have not been directly involved in this. This is, as you know, a covert action. And, as Secretary Kerry noted, probably to [go] into much more detail would—would require a closed or classified hearing."


Adam Entous, Julian E. Barnes and Siobhan Gorman, "U.S. Begins Shipping Arms for Syrian Rebels," Wall Street Journal, June 26, 2013; Greg Miller, "CIA ramping up covert training program for moderate Syrian rebels," Washington Post, October 2, 2013; Greg Miller and Karen DeYoung, "Secret CIA effort in Syria faces large funding cut," Washington Post, June 12, 2015.


See Harakat Hazm YouTube Channel, April 15, 2014, at


Tom Bowman and Alice Fordham, "CIA Is Quietly Ramping Up Aid To Syrian Rebels, Sources Say," National Public Radio (Online), April 23, 2014.


Adam Entous, "U.S. Sees Russian Drive Against CIA-Backed Rebels in Syria," Wall Street Journal, October 5, 2015.


"Trump ends covert CIA program to arm anti-Assad rebels in Syria, a move sought by Moscow," Washington Post, Jul7 19, 2017.


The FY2014 assistance authorities [Section 7041(i) of Division K of P.L. 113-76], as expanded and extended by the FY2015 Appropriations Act [Section 7041(h) of Division J of P.L. 113-235], made FY2015 and prior year ESF funding available "notwithstanding any other provision of law" for select nonlethal purposes. The FY2016 Appropriations Act [Section 7041(h) of P.L. 114-113] extended this authority further, granting notwithstanding exceptions for FY2016 ESF funds as well as for FY2016 funds in the International Narcotics Control and Law Enforcement (INCLE) and Peacekeeping Operations (PKO) accounts. The Obama Administration used the INCLE and PKO accounts to support justice sector activities in opposition-held areas of Syria and to provide nonlethal assistance to select armed opposition groups. The FY2017 Consolidated Appropriations Act [Section 7041(j) of Division J of P.L. 115-31] further amended and expanded the categories of assistance authorized to be provided from these accounts for FY2017. The terms of the FY2017 act apply to funds available pursuant to FY2018 continuing resolutions.


Prior to the enactment of the expanded congressional authorization in 2013, U.S. assistance had been provided to select unarmed opposition groups and opposition-held communities on a periodic basis from May 2012 onward.


In August 2015, the State Department reported that "Non-lethal assistance is being provided to a range of civilian opposition groups, including local councils, civil society organizations, and SOC-affiliated entities to bolster their institutional capacity, create linkages among opposition groups inside and outside Syria, and help counter violent extremism. These efforts enable the delivery of basic goods and essential services to liberated communities as they step in to fill voids in local governance. In addition to civil administration training programs, we have provided opposition groups with a wide array of critical equipment, including generators, ambulances, cranes, dump trucks, fire trucks, water storage units, search and rescue equipment, educational kits for schools, winterization materials, and commodity baskets for needy families in the local community." Office of the State Department Spokesperson, "Syrian Crisis: U.S. Efforts and Assistance," August 7, 2015.


Per Section 7041(j) of Division J of P.L. 115-31, the FY2017 Consolidated Appropriations Act.


That strategy must include a "mission statement, achievable objectives and timelines, and a description of inter-agency and donor coordination and implementation of such strategy." The strategy, which may be classified, must also include "a description of oversight and vetting procedures to prevent the misuse of funds."


Prior to the FY2016 Appropriations Act, the relevant authorities for Syria applied to Economic Support Fund (ESF) monies only. The Obama Administration obligated funds from other accounts using emergency and contingency authorities. In the House FY2018 Foreign Operations appropriations bill, Bilateral Economic Assistance accounts in Division G, Title III include ESF - Economic Support Fund; Democracy Fund (DF); Transition Initiatives (TI); Development Assistance, and other accounts. The Senate bill would authorize the use of funds from the following accounts ESF; INCLE - International Narcotics Control and Law Enforcement; NADR - Nonproliferation, Anti-terrorism, Demining and Related Programs; and PKO - Peacekeeping Operations.


Opposition infighting in late 2013 led to the capture of some nonlethal U.S. assistance by Islamist groups. U.S. officials subsequently revisited some delivery and monitoring mechanisms and worked to improve the reliability and security of delivery channels. Dasha Afanasieva and Humeyra Pamuk, "U.S., Britain suspend aid to north Syria after Islamists seize weapons store," Reuters, December 11, 2013.


State Department Bureau of Population, Refugees, and Migration, U.S. Humanitarian Assistance in Response to the Syrian Crisis, April 5, 2017. See also USAID, Syria–Complex Emergency, Fact Sheet #4, Fiscal Year (FY) 2017, April 27, 2017.


USAID, Fact Sheet: U.S. Assistance for the People of Syria, January 26, 2018.


Prepared by Mary Beth Nikitin, Specialist in Nonproliferation. See also CRS Insight IN10771, Syria's Chemical Weapons: Continuing Challenges, by [author name scrubbed].


"Chemical Weapons Attack in Saraqib, Syria," State Department Press Statement, February 5, 2018,


The Syrian government in 2013 joined the Chemical Weapons Convention (CWC), which bans the use of any toxic chemicals in warfare and requires—along with U.N. Security Council resolutions—that Syria destroy all of its chemical weapons stocks and production facilities under international supervision.


Hearing on Worldwide Threats, Senate Select Committee on Intelligence, May 11, 2017.


Statement by Kenneth D. Ward, Permanent Representative of the United States of America to the OPCW, at the Eighty-Sixth Session of the Executive Council, October 20, 2017.


"Trump Orders Missile Attack in Retaliation for Syrian Chemical Strikes," DoD News, April 6, 2017.


Statement by President Trump on Syria, April 6, 2017.


Rex Tillerson, Secretary of State, Remarks with National Security Advior H.R. McMaster, April 6, 2017.


World Health Organization, "WHO Alarmed by Use of Highly Toxic Chemicals in Syria," press release, April 5, 2017.


Some victims of the attack were moved to Turkey for treatment, where experts could assess their symptoms and likely causes. Louisa Loveluck, "Deadly Nerve Agent Sarin Used in Deadly Attack," Washington Post, April 6, 2017.


"OPCW Director-General Shares Incontrovertible Laboratory Results Concluding Exposure to Sarin," OPCW Press Release, April 19, 2017.


White House Office of the Press Secretary, Government Assessment of the Syrian Government's Use of Chemical Weapons on August 21, 2013, August 30, 2013.


Chapter VII of the U.N. Charter authorizes the use of punitive measures such as sanctions or military force.


Organization for the Prohibition of Chemical Weapons, "Destruction of Syrian Chemical Weapons Completed," press release, January 4, 2016.


"Note by the Director General: Progress in the Elimination of the Syrian Chemical Weapons Programme," EC-86/DG.23, September 25, 2017.


Joint News Conference with Secretary Mattis and Minister of Defense Lieberman in Tel Aviv, Israel, Department of Defense News Transcript, April 21, 2017; Julian E. Barnes and Maria Abi-Habib, "Syrian Attack Defies 2013 Chemical-Weapons Deal," Wall Street Journal, April 6, 2017.




UN Commission of Inquiry Info Graphic: Chemical Weapons Attacks Documented by the U.N. Commission of Inquiry on the Syrian Arab Republic, as of September 6, 2017; Arms Control Association, "Timeline of Chemical Weapons Attacks in Syria: 2012-2017," fact sheet, 2017.


Reports by U.N. Member States have been made via confidential correspondence, such as letters containing allegations described generally in the December 2013 final report of U.N. Mission to Investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic (the U.N. Mission). See U.N. Mission, Final Report, December 12, 2013, pp. 2-6.


The U.N. Mission to investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic released its report on September 16, 2013, concluding that surface-to-surface rockets containing the chemical weapons nerve agent sarin were used in the Ghouta area of Damascus against civilians on a "relatively large scale." The 2013 U.N. investigative mission was not tasked with assigning culpability for the attacks.


See U.N. Mission, Final Report, December 12, 2013; and OPCW Fact-Finding Mission (FFM) in Syria, Final Report, December 2015, attached to "Letter dated 27 January 2016 from the Secretary-General addressed to the President of the Security Council," S/2016/85, January 28, 2016.


Resolution 2235 required that the U.N. Secretary-General, in coordination with the OPCW Director-General, submit within 20 days recommendations for its approval on the establishment of a Joint Investigative Mechanism "to identify to the greatest extent feasible individuals, entities, groups, or governments who were perpetrators, organisers [sic], sponsors or otherwise involved in the use of chemicals as weapons, including chlorine or any other toxic chemical, in the Syrian Arab Republic where the OPCW FFM determines or has determined that a specific incident in the Syrian Arab Republic involved or likely involved the use of chemicals as weapons, including chlorine or any other toxic chemical…."


Letter dated 24 August 2016 from the Leadership Panel of the Organization for the Prohibition of Chemical Weapons-United Nations Joint Investigative Mechanism addressed to the Secretary-General, S/2016/738; Letter dated 21 October 2016 from the Leadership Panel of the Organization for the Prohibition of Chemical Weapons-United Nations Joint Investigative Mechanism addressed to the Secretary-General, S/2016/888.


The JIM report states that OPCW experts were able to identify that the sulfur mustard was produced by the Islamic State because of the way it was produced, which was different from Syrian government stocks. "The OPCW confirmed that the sulfur mustard from the Syrian Arab Republic did not contain impurities such as polysulphides, meaning that a different process was used by the Government. The OPCW also reported that the sulfur mustard used by ISIL in northern Iraq on several occasions in 2015 and 2016 was produced through the Levinstein process." Ibid, p. 97.


"Syria: Renewal of the UN-OPCW Joint Investigative Mechanism," What's In Blue, November 17, 2016.


Mark Toner, Deputy State Department Spokesman, "The Fourth Report of the Joint Investigative Mechanism," Press Statement, October 28, 2016.


"Launch of the International Partnership against Impunity for the Use of Chemical Weapons," French Foreign Ministry, January 23, 2018,


On August 7, the Permanent Representative of Syria to the United Nations Dr. Bashar Jaafari told the United Nations Security Council that, "the Syrian Government and the Syrian army have never used chemical weapons, and never will. Contrariwise, Syria's army and its civilians have been targeted with toxic chemicals and chemical weapons, including chlorine gas, by armed terrorist groups, such as Daesh [Arabic acronym for ISIL] and the Al-Nusra Front, in many parts of Syria… ." He accused unspecified investigation missions of having "based their work on false, fabricated statements made by parties well known to all. Those missions have carried out partial and biased investigations—outside Syria—without a modicum of coordination with the Syrian authorities." (U.N. Document S/PV.7501.) The U.N. and OPCW investigative missions have worked inside Syria with the permission of the Syrian government. In 2011, the U.N. Human Rights Council established an Independent International Commission of Inquiry on the Syrian Arab Republic that has reported extensively on the conflict, including on alleged chemical attacks. The commission uses a "reasonable grounds to believe" standard of evidence and relies on first-hand accounts from Syrians now in neighboring countries, remote interviews, and other publicly available information.


"Syria Draft Resolution Imposing Sanctions Regarding the Use and Production of Chemical Weapons," What's In Blue, February 25, 2017.


"U.S. Tests Show Mustard Gas Traces in Islamic State Attack," The Washington Post, August 21, 2015.


Slovenia Press Agency, "IS Likely Used Chemical Weapons in Syria, Iraq; Could Use Them Elsewhere, OPCW Head Says," May 11, 2016.


"U.S.: Shell That Hit Iraqi Base Contained Sulfur-Mustard Agent," Associated Press, September 22, 2016; "U.S. Troops Brace for More Mustard Attacks," Military Times, September 27, 2016.


"ISIS Militants Launch Multiple Chemical Weapons Attacks on Iraqi Troops," Newsweek, April 17, 2017; "Chemical Attacks and Narrow Streets Complicate Fight for Mosul's Old City, "Al-Monitor, April 2017; "The Islamic State threatens more chemical attacks in Mosul after loss of senior ISIS commander," SOFREP News, April 20, 2017.


On the Record Press Gaggle by Secretary James N. Mattis, February 11, 2018.


"Terrorist Designations of the al-Nusrah Front as an Alias for al-Qa'ida in Iraq," Press Statement by State Department Spokesperson Victoria Nuland, December 11, 2012.


President Barack Obama, Remarks by the President to the White House Press Corps, August 20, 2012.


Action Group for Syria, Final Communiqué, June 30, 2012.


Letter dated 22 March 2013 from the Secretary-General addressed to the President of the Security Council, U.N. Document S/2013/184, March 22, 2013.


The White House, Government Assessment of the Syrian Government's Use of Chemical Weapons on August 21, 2013, August 30, 2013. United Nations investigations confirmed that a chemical attack took place but its September and December 2013 reports did not address attribution. See U.N. Document A/67/997–S/2013/553, Report of the United Nations Mission to Investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic on the alleged use of chemical weapons in the Ghouta area of Damascus on 21 August 2013, September 16, 2013; and, United Nations Mission to Investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic, Final Report, December 2013.


President Barack Obama, Remarks by the President Before Meeting with Members of Congress on the Situation in Syria, September 3, 2013.


The FY2015 Continuing Resolution (P.L. 113-164, "the FY2015 CR") contained temporary authorization for the training and equipping of vetted Syrians that differed from the Administration's requests and expired on December 11, 2014. The FY2015 NDAA (Sections 1209, 1510, and 1534 of Division A of P.L. 113-291) and the Consolidated and Further Continuing Appropriations Act, 2015 ("Counterterrorism Partnership Fund" and Section 9016 of P.L. 113-235) provided further authority and funding guidance for the program.


President Trump Statement on Syria, April 6, 2017; and, Statement from Pentagon Spokesman Capt. Jeff Davis on U.S. strike in Syria, Release No: NR-126-17, April 6, 2017.


Statement by Secretary of Defense Jim Mattis on the U.S. Military Response to the Syrian Government's Use of Chemical Weapons, April 10, 2017; Press Conference by Secretary Mattis and Gen. Votel in the Pentagon Briefing Room, April 11, 2017.