Yemen: Civil War and Regional Intervention

Yemen: Civil War and Regional Intervention
March 12November 23, 2021 , 2021
For over a decade, the Republic of Yemen has been torn apart by multiple armed For over a decade, the Republic of Yemen has been torn apart by multiple armed
conflicts to which several internal militant groups and foreign nations are parties. conflicts to which several internal militant groups and foreign nations are parties.
Collectively, these Jeremy M. Sharp
Collectively, these conflicts have eroded central governance in Yemenconflicts have eroded central governance in Yemen, and have
Specialist in Middle
fragmented the nation into various and hav e fragmented the nation into various Specialist in Middle local centers of power. The gradual dissolution of local centers of power. The gradual dissolution of
Eastern Affairs
Yemen’s territorial integrity has alarmed the Yemen’s territorial integrity has alarmed the Eastern Affairs United States and others in the international United States and others in the international

community. Policymaker concerns include fears that community. Policymaker concerns include fears that state failure may empower Yemen-state failure may empower Yemen-

based transnational terrorist groups; destabilize vital international shipping lanes near based transnational terrorist groups; destabilize vital international shipping lanes near
the Bab al Mandab strait (also spelled Bab al Mandeb, Bab el the Bab al Mandab strait (also spelled Bab al Mandeb, Bab el Mendeb); and provide opportunities for Iran to Mendeb); and provide opportunities for Iran to
threaten Saudi Arabia’s borders.threaten Saudi Arabia’s borders.
Beyond geo-strategic concerns, the collapse of Yemeni institutions during wartime has exacerbated poor living Beyond geo-strategic concerns, the collapse of Yemeni institutions during wartime has exacerbated poor living
conditions in what has long been the most impoverished Arab country, leading to what is now considered conditions in what has long been the most impoverished Arab country, leading to what is now considered one of the the
world’s worst humanitarian crisis. This report provides information on these ongoing and overlapping crises.world’s worst humanitarian crisis. This report provides information on these ongoing and overlapping crises.
In 2014, the northern Yemeni-based Ansar Allah/Houthi movement (referred to in this report as “the Houthis”) In 2014, the northern Yemeni-based Ansar Allah/Houthi movement (referred to in this report as “the Houthis”)
took over the capital, took over the capital, SanaaSana’a (also commonly spelled (also commonly spelled Sana’aSanaa), and in early 2015, advanced southward from the ), and in early 2015, advanced southward from the
capital to Aden on the Arabian Sea. In March 2015, after Yemeni President Abdu Rabbu Mansour Hadi, who had capital to Aden on the Arabian Sea. In March 2015, after Yemeni President Abdu Rabbu Mansour Hadi, who had
fled to Saudi Arabia, appealed for international intervention, Saudi Arabia assembled a coalition of several of its fled to Saudi Arabia, appealed for international intervention, Saudi Arabia assembled a coalition of several of its
Arab partners (referred to in this report as “the Saudi-led coalition”) and launched a military offensive aimed at Arab partners (referred to in this report as “the Saudi-led coalition”) and launched a military offensive aimed at
restoring Hadi’s rule and dislodging Houthi fighters from the capital and other major cities. restoring Hadi’s rule and dislodging Houthi fighters from the capital and other major cities.
Since then, the conflict in Yemen has killed tens of thousands, caused significant humanitarian suffering, and has Since then, the conflict in Yemen has killed tens of thousands, caused significant humanitarian suffering, and has
significantly damaged the country’s infrastructure. One U.S.- and European-funded organization, the Armed significantly damaged the country’s infrastructure. One U.S.- and European-funded organization, the Armed
Conflict Location & Event Data Project (ACLED), estimates as of Conflict Location & Event Data Project (ACLED), estimates as of November 2020October 2021 that more than that more than 130145,000 ,000
Yemenis have been killed since 2015. Yemenis have been killed since 2015.
Although media coverage of the Saudi-led intervention has characterized the war as a binary conflict (the Saudi- Although media coverage of the Saudi-led intervention has characterized the war as a binary conflict (the Saudi-
led coalition versus the Houthis), there actually have been a multitude of combatants whose alliances and loyalties led coalition versus the Houthis), there actually have been a multitude of combatants whose alliances and loyalties
have been somewhat fluid. In summer 2019 in southern Yemen, long-simmering tensions between the have been somewhat fluid. In summer 2019 in southern Yemen, long-simmering tensions between the
internationally recognized Republic of Yemen government (ROYG) and the separatist Southern Transitional internationally recognized Republic of Yemen government (ROYG) and the separatist Southern Transitional
Council (STC) boiled over, leading to open warfare between the local allies of Saudi Arabia and the United Arab Council (STC) boiled over, leading to open warfare between the local allies of Saudi Arabia and the United Arab
Emirates. Emirates. In 2020Since then, periodic clashes , periodic clashes have continued, though both sides finally implemented a power sharing agreement continued, though both sides finally implemented a power sharing agreement
at the end of at the end of the year2020 and formed a and formed a tenuous coalition government. Since early 2020, Houthi forces have continued to launch attacks against the ROYG in Marib governorate. The Marib governorate is the last northern stronghold of the ROYG. During summer and fall 2021, momentum shifted in favor of the Houthis, as their fighters have gradually attempted to encircle Marib city, the governorate’s eponymous capital. Between September and October 2021, the Houthis captured five districts in the governorates of Marib and Shabwa, effectively cutting off the southern road linking Marib City to Shabwa—a key route for the resupply of ROYG forces. The Houthis have made significant territorial gains in Marib and may be on the cusp of forcing ROYG forces to surrender or negotiate a cease-firecoalition government. .
Many foreign observers have denounced human rights violations that they charge have been committed by all Many foreign observers have denounced human rights violations that they charge have been committed by all
parties to the conflict. In the United States and some European countries, there has been vociferous opposition to parties to the conflict. In the United States and some European countries, there has been vociferous opposition to
Saudi-led coalition air strikes that hit civilian targets, leading Congress to debate and enact some legislation to limit U.S. coalition air strikes that hit civilian targets, leading Congress to debate and enact some legislation to limit U.S.
support for the coalition. Some in Congress opposed to such efforts have highlighted Iran’s support for the support for the coalition. Some in Congress opposed to such efforts have highlighted Iran’s support for the
Houthis as a major factor in Yemen’s destabilization.Houthis as a major factor in Yemen’s destabilization.
For several years, Yemen has been considered For several years, Yemen has been considered one of the worst humanitarian the worst humanitarian crisiscrises in the world, and public health in the world, and public health
experts warn that the Coronavirus Disease 2019 (COVID-19)experts warn that the Coronavirus Disease 2019 (COVID-19) pandemic pandemic may haveis having significant negative effects on significant negative effects on
Yemen’s vulnerable population. To date, most humanitarian agencies believe that the extent of the outbreak in Yemen’s vulnerable population. To date, most humanitarian agencies believe that the extent of the outbreak in
Yemen has been underreported. Yemen has been underreported.
For additional information on Yemen, including a summary of For additional information on Yemen, including a summary of relevant legislationlegislation under consideration in the 117th Congress, please see CRS Report , please see CRS Report
R45046, R45046, Congress and the War in Yemen: Oversight and Legislation 2015-20202021, by Jeremy M. Sharp, Christopher , by Jeremy M. Sharp, Christopher
M. Blanchard, and Sarah R. Collins.M. Blanchard, and Sarah R. Collins.
Congressional Research Service Congressional Research Service

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Yemen: Civil War and Regional Intervention


Congressional Research Service

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Contents
Overview ............................................................................................................................. 1 Conflict Update ........................ 1
Recent Changes in U.S. Policy ................................................................................................. 1
2 The Houthi-ROYG War in the North: The Battle for Marib .............................................. 2 Other Houthi Military Gains........................................................................................ 3 The Port of Hudaydah .......... 4
Clashes Continue in Hudaydah ............................................................................................. 5 The Maritime Blockade and Fuel Shipments into Hudaydah ... 5
Failing Oil Tanker .................................... 5 Failing Oil Tanker .................................................................................... 5............ 7
The Houthi-Saudi Arabia Conflict ............................................................................................ 6
Southern Yemen: Tentative Unity between the ROYG and STC 8 Peace Efforts Stal ........................................................................................................... 79
Iranian Support to the Houthis .................................................................................................. 8
Yemen’s Humanitarian Crisis ............. 10 Southern Yemen: Tentative Unity between the ROYG and STC............................................ 11 Biden Administration Policy...................................................................................... 8
Food Insecurity & Humanitarian Access 12 Yemen’s Humanitarian Crisis ................................................................................. 8
The COVID-19 Pandemic in Yemen... 14 Food Insecurity & Humanitarian Access ................................................................ 15 The COVID-19 Pandemic in Yemen................................ 10
International Pledges for Yemen ...................................................... 16 International Pledges for Yemen ................................. 10
Conflict Analysis .......................................... 17 Conflict Analysis ............................................................................................ 11......... 17

Figures
Figure 1. Lines of Control in Yemen .Marib Governorate.............................................................................................. 3
Figure 2. Lines of Control in Marib Governorate Yemen................................................................................... 4
Figure 3. U.N. Monitors in Hudaydah ............................................................................................. 5
Figure 4. Saudi-led Coalition Air Strikes Perper Month ...................................................................... 7 9
Figure 5. World Food Programme: Emergency Dashboard Yemen ................................................. 9

16 Contacts
Author Information ........................................................................................................................ 12 19

Congressional Research Service Congressional Research Service

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Yemen: Civil War and Regional Intervention

Overview
For over a decade, the Republic of For over a decade, the Republic of Yemen1Yemen has been torn apart by multiple armed conflicts to has been torn apart by multiple armed conflicts to
which several internal militant groups and foreign nations are parties.which several internal militant groups and foreign nations are parties.1 Collectively, these Collectively, these conflicts conflicts
have eroded central governance in Yemenhave eroded central governance in Yemen, and have fragmented the nation into various local and have fragmented the nation into various local
centers of power. The gradual dissolution of Yemen’s territorial integrity has alarmed the United centers of power. The gradual dissolution of Yemen’s territorial integrity has alarmed the United
States and others in the international community. Policymaker concerns include fears that state States and others in the international community. Policymaker concerns include fears that state
failure may empower Yemen-based transnational terrorist groups; destabilize vital international failure may empower Yemen-based transnational terrorist groups; destabilize vital international
shipping lanes near the Bab al Mandab strait2 (also shipping lanes near the Bab al Mandab strait2 (also spelledspel ed Bab al Mandeb, Bab el Mendeb); and Bab al Mandeb, Bab el Mendeb); and
provide opportunities for Iran to threaten Saudi Arabia’s borders. Beyond geo-provide opportunities for Iran to threaten Saudi Arabia’s borders. Beyond geo- strategic concerns, strategic concerns,
the collapse of Yemeni institutions during wartime has exacerbated poor living conditions in what the collapse of Yemeni institutions during wartime has exacerbated poor living conditions in what
has long been the most impoverished Arab country, leading to what is now has long been the most impoverished Arab country, leading to what is now considered considered one of the world’s the world’s
worst humanitarian worst humanitarian crisis.
As of March 2021, Yemen remains beset by multiple armed and political conflicts which, in their
totality, have crippled central governance, devastated the national economy, and exacerbated a
long-standing humanitarian crisis. One U.S.- and European-funded organization, the Armed
Conflict Location & Event Data Project (ACLED), estimates that from the start of regional
intervention in Yemen in March 2015 until November 2020, over 130,000 Yemenis had been
killed in various acts of violence.3
Recent Changes in U.S. Policy
crises. Since March 2015, Saudi Arabia and members of a coalition it established have been engaged in Since March 2015, Saudi Arabia and members of a coalition it established have been engaged in
military operations in Yemen against the Houthi movement, or military operations in Yemen against the Houthi movement, or Ansar Allah, which the U.S. , which the U.S.
government believes receives some material support from Iran. As of government believes receives some material support from Iran. As of FebruaryNovember 2021, the 2021, the
epicenter of fighting was around the northern governorate and city of Maribepicenter of fighting was around the northern governorate and city of Marib (see Figure 2), one , one
of the last areas under the control of the of the last areas under the control of the internationallyinternational y-recognized Republic of Yemen -recognized Republic of Yemen
Government (ROYG) led Government (ROYG) led by Yemeni President Abdu Rabbu Mansour Hadi. by Yemeni President Abdu Rabbu Mansour Hadi.

1 Since its 1990 unification, Yemen has been a republic As of November 2021, Yemen remains beset by multiple armed and political conflicts which, in their totality, have crippled central governance, devastated the national economy, and exacerbated a long-standing humanitarian crisis. The Armed Conflict Location & Event Data Project (ACLED) estimates that from the start of regional intervention in Yemen in March 2015 until October 2021, over 145,000 Yemenis had been kil ed in various acts of violence.3 1 Formerly the Republic of North Yemen and the People’s Democratic Republic of [South] Yemen, Yemen has been a unified republic since 1990 in which, according to Article 4 of its 2001 constitution (as in which, according to Article 4 of its 2001 constitution (as
amended), “amended), “TheT he people of Yemen are the possessor and the source of power, which they exercise directly through people of Yemen are the possessor and the source of power, which they exercise directly through
public public referendums and elections, or indirectly through the legislative, executive and judicialreferendums and elections, or indirectly through the legislative, executive and judicial authorities, as wellauthorities, as well as as
through elected local councils.” In realitythrough elected local councils.” In reality, from 1990 to 2012, the late President Ali Abdullah Saleh, the late President Ali Abdullah Saleh ruled a ruled the unified Yemen unified Yemen from 1990-
2012. After popular uprisings swept across the Arab world in 2011, including in Yemen, the Gulf Cooperation Council
(GCC) continuously, centralizing power and control under his auspices through partnerships with foreign powers and local power brokers. After popular uprisings swept across the Arab world in 2011, including in Yemen, the Gulf Cooperation Council (GCC) helped broker a transition plan for Yemen, which washelped broker a transition plan for Yemen, which was endorsed endorsed by the United Nations (see, U.N. Security by the United Nations (see, U.N. Security
Council Resolution 2014) and supersededCouncil Resolution 2014) and superseded the authority of Yemen’s constitution. As part of Yemen’s transition from the authority of Yemen’s constitution. As part of Yemen’s transition from
the longtime rule of President Saleh to the longtime rule of President Saleh to interim President HadiPresident Hadi (Saleh’s long-time Vice President), all of Yemen’s various political factions (565 individual , all of Yemen’s various political factions (565 individual
delegates) held what wasdelegates) held what was called called the National Dialogue Conference (NDC) from 2013-2014. the National Dialogue Conference (NDC) from 2013-2014. ThatT hat conference was conference was
intended to settle all of Yemen’s outstanding political issues,intended to settle all of Yemen’s outstanding political issues, including producing recommendations which were to be including producing recommendations which were to be
used used by a Constitutional Drafting Committee to create a new constitution, which wouldby a Constitutional Drafting Committee to create a new constitution, which would then be voted on in a national then be voted on in a national
referendum. referendum. HoweverHowev er, in January 2014 the NDC ended without agreement, in January 2014 the NDC ended without agreement and shortly thereafter, the Houthis launched and shortly thereafter, the Houthis launched
a military offensive to seize large swathsa military offensive to seize large swaths of northern Yemen, culminating in their capture of the capital of northern Yemen, culminating in their capture of the capital Sana’aSanaa in in
September 2014September 2014 . .
2 After the Straits of Hormuz and Malacca, the Bab2 After the Straits of Hormuz and Malacca, the Bab al Mandab isal Mandab is one of the world’sone of the world’s busiest busiest chokepoints in terms of chokepoints in terms of
volume of crudevolume of crude oil and petroleum liquidsoil and petroleum liquids transported through each day. According to the Energy Information transported through each day. According to the Energy Information
Administration, “Administration, “Total T otal petroleum flows through the Bab el-Mandeb Strait accounted for about 9% of total seaborne- petroleum flows through the Bab el-Mandeb Strait accounted for about 9% of total seaborne-
traded petroleum (crude oil and refined petroleum products) in 2017.” See, U.S. Energy Information Administration, traded petroleum (crude oil and refined petroleum products) in 2017.” See, U.S. Energy Information Administration,
““TheT he Bab el-Mandeb Bab el-Mandeb Strait is a Strategic Route for Oil and Natural GasStrait is a Strategic Route for Oil and Natural Gas Shipments, AugustShipments, August 27, 2019. 27, 2019.
3 3 TheT he Armed Conflict Location & Event Data Project (ACLED), Dashboard, available online at Armed Conflict Location & Event Data Project (ACLED), Dashboard, available online at:
[ https://acleddata.com/dashboard/#/dashboardhttps://acleddata.com/dashboard/#/dashboard]. Congressional Research Service 1 Yemen: Civil War and Regional Intervention Conflict Update The Houthi-ROYG War in the North: The Battle for Marib Since early 2020, Houthi forces have continued to launch attacks against the forces of the Republic of Yemen Government (ROYG) in Marib governorate. The Marib governorate is the last northern stronghold of the ROYG. Marib is the center of Yemen’s modest hydrocarbon sector and, while the country imports over 90% of its oil and gas, Marib contains several oil fields (where Exxon and Total SA have concessions) and an oil refinery that accounts for nearly 8% of Yemen’s total energy needs.4 Marib also contains a power plant and a liquefied petroleum bottling plant that produces cooking gas for a significant segment of the population. At first, the Houthi’s offensive against Marib made only incremental progress.5 During the spring and early summer of 2021, the Houthis took heavy casualties from Saudi-led coalition air strikes. The terrain near Marib city itself is relatively flat desert plain, which exposes the Houthi ranks and make it more chal enging for their fighters, who are accustomed to fighting on mountainous terrain.6 During summer and fal 2021, momentum shifted in favor of the Houthis, as their fighters have gradual y attempted to encircle Marib city, the governorate’s eponymous capital. Between September and October 2021, the Houthis captured five districts in the governorates of Marib (see Figure 1) and Shabwa (a governorate which also has oil fields and the country’s sole liquefied natural gas terminal), effectively cutting off the southern road linking Marib City to Shabwa—a key route for the resupply of ROYG forces.7 In early 2021, Marib was home to an estimated 800,000 internal y displaced persons (IDPs), who fled conflict in other parts of the country.8 Now, with the conflict having spread throughout the province, Marib residents are now being displaced. In early October 2021, the International Organization for Migration announced fighting during September had displaced 10,000 people, the most in a single month in 2021.9 In an attempt to support ROYG forces and prevent further Houthi encroachment on Marib City, the Saudi-led coalition has repeatedly conducted air strikes against Houthi ground forces. Throughout September and October 2021, the Saudi Press Agency has published near daily reports of the Houthi death toll from coalition air strikes. From October 12 to October 26, the coalition claims to have kil ed over 1,800 Houthi fighters.10 However, according to Elana DeLozier, a senior fel ow at the Washington Institute for Near East Policy, “You can’t real y win a war with air power... And this is where the government real y gets itself into trouble because it 4 International Crisis Group, “Crisis in Marib: Averting a Chain Reaction in Yemen,” February 22, 2021. 5 Samy Magdy, “Grueling Battle for Key Yemeni City; T oll Keeps Rising as Rebels T ry to Complete T heir Hold on the North But Gain Little,” Associated Press, July 12, 2021. 6 Michael Horton, “Yemen’s Fate Hinges on T he Battle for Marib,” The Jamestown Foundation, Terrorism Monitor, Volume: 19 Issue: 4, February 26, 2021. 7 “Yemen’s Houthis Advance in Shabwa and Marib,” Reuters, October 17, 2021. 8 Office of the United Nations High Commissioner for Human Rights (UNHCR), “Press briefing notes on Yemen,” February 19, 2021. 9 Samy Magdy, “UN: 10,000 Displaced as Clashes Escalate Over Key Yemen City,” Associated Press, October 7, 2021. 10 “Saudi Coalition Says Killed 85 rebels Around Yemen’s Marib,” Agence France Presse, October 26, 2021. Congressional Research Service 2 Yemen: Civil War and Regional Intervention doesn’t have enough oomph to push out the Houthis, so it’s just the Saudi airstrikes [holding them back].”11 According to one estimate, the Houthis have lost nearly 15,000 fighters since June, while ROYG-aligned forces fighting in Marib have lost 1,200.12 Figure 1.Marib Governorate Source: United Nations Office for the Coordination of Humanitarian Affairs Other Houthi Military Gains Beyond Marib, the Houthis continue to gain territory on the ground, while using unmanned aerial vehicles (UAVs) and rockets and missiles to threaten their opponents in other parts of Yemen beyond their immediate control. Recent notable Houthi campaigns/attacks include:  In 2021 in the central governorate of Al Bayda, forces aligned with the ROYG initial y pushed the Houthis back. However, in September 2021, the Houthis declared full control over the governorate. According to the International Crisis Group, “Since late September [2021], the Houthis have used al-Bayda as the launching pad for a multi-front campaign in western Shebwa [Shabwa] and northern Abyan.... These moves appear to be aimed at cutting off the major roads linking the three governorates, and the various anti-Houthi forces based inside 11 Siobhán O’Grady and Ali Al Mujahed, “Battle for the Badlands: Yemen’s Seven -Year Civil War Could T urn on Fierce Fighting in Remote Marib Province,” Washington Post, October 1, 2021. 12 T alek Harris, “Yemen 'Confident' of Holding Key City of Marib, FM Says,” Agence France Presse, November 21, 2021. Congressional Research Service 3 Yemen: Civil War and Regional Intervention them, as wel as at providing Houthi forces with new routes into southern Yemen.”13  In August 2021, a Houthi UAV attack against a military base in the southern governorate of Lahj kil ed at least 30 soldiers.14 A month later, a combined Houthi UAV/missile attack struck the port of Mokha, destroying several warehouses fil ed with humanitarian goods. The attack coincided with the visit of the ROYG Ministry of Transportation to mark the reopening of Mokha commercial port, which had been closed for several years. Figure 2. Lines of Control in Yemen As of October 2021 Source: Graphic created by CRS using data from Risk Intel igence (2021); Esri (2017 & 2018); NOAA (2018); USGS (2018); Department of State (2015). 13 International Crisis Group, “After al-Bayda, the Beginning of the Endgame for Northern Yemen,” Briefing 84, Middle East & North Africa, Oct ober 14, 2021. 14 Olivia Harper, “Ansar Allah Ballistic Missile and UAV Attack Demonstrates Extensive Weapons Arsenal and Enhanced Operational Capabilities,” Jane's Terrorism & Insurgency Monitor, September 8, 2021. Congressional Research Service 4 Yemen: Civil War and Regional Intervention The Port of Hudaydah In December 2018, the United Nations brokered a cease-fire, known as the Stockholm Agreement,15 centered on the besieged Red Sea port city of Hudaydah (also spel ed Hodeidah, Al Hudaydah). Nearly three years later, the agreement remains unfulfil ed. Currently, the Houthis control the port and city of Hudaydah itself, along with access to Figure 3. U.N. Monitors in Hudaydah the city from the north. To the south along the Red Sea coast, a coalition of forces (dubbed the “Joint Resistance Forces”) led by Tareq Saleh, the nephew of the late former Yemeni President Ali Abdullah Saleh, had remained ensconced there since 2018, when the Saudi-led coalition attempted to seize Hudaydah from the Houthis before the Stockholm Agreement halted the fighting. Tareq Saleh’s forces had been based out of the port town of Mokha and receive support from Saudi Arabia and the United Arab Emirates. They are not formal y part of the ROYG and operate independently from President Hadi. Source: Twitter, U.N. Mission to support the Hudaydah Agreement, October 15, 2020. In November 2021, elements of the Joint Resistance Forces suddenly withdrew from their positions around Hudaydah City. Houthi forces then immediately moved in. However, other militias within the Joint Resistance Forces opted to fight Houthi forces in Hudaydah governorate, as major clashes and air strikes resumed in and around Hudaydah for the first time since 2018. After the reported redeployment of the Joint Resistance Forces, Saudi Arabia denied that it was abandoning its support for local Yemeni forces and withdrawing from Yemen.16 It is possible that Saudi Arabia may be seeking local reinforcements to counter the Houthis siege of Marib. The Maritime Blockade and Fuel Shipments into Hudaydah On April 14, 2015, the U.N. Security Council adopted Resolution (UNSCR) 2216, which imposed sanctions on individuals undermining the stability of Yemen and authorized an arms embargo against the Houthis and their al ies. The resolution also demanded that the Houthis withdraw from al areas seized during the current conflict, relinquish arms seized from military and security institutions, cease al actions fal ing exclusively within the authority of the legitimate Government of Yemen, and fully implement previous Council resolutions. UNSCR 2216 authorizes U.N. member states to prevent the transfer or sale of arms to the Houthis and al ows “states neighboring Yemen” to inspect cargo suspected of carrying arms to Houthi 15 T he Stockholm Agreement consists of three components: (1) a cease-fire around the port city of Hudaydah, (2) a 15,000-person prisoner swap, and (3) a statement of understanding that all sides would form a committee to discuss the war-torn city T aiz. T he United Nations agreed to chair a Redeploy ment Coordination Committee (RCC) to monitor the cease-fire and redeployment. In January 2019, the United Nations Security Council passed UNSCR 2452, which authorized the creation of the United Nations Mission to support the Hudaydah Agreement (UNMHA), of which the RCC was a significant component. It has since been reauthorized until July 2022. 16 “Clashes Erupt in Yemen's Hodeidah as Pro-Coalition Forces Cede Ground to Houthis,” Reuters, November 14, 2021. Congressional Research Service 5 Yemen: Civil War and Regional Intervention fighters. Since the start of hostilities in Yemen, Iran has continued to support Houthi militias with weapons shipments, fueling the desire of the Saudi-led coalition to thwart Iranian weapons smuggling by sea (see below). Between 2015 and 2016, the Saudi-led coalition conducted its own exclusive naval blockade of Yemen’s ports in order to deter Iranian weapons smuggling. The initial blockade also slowed the delivery of commercial goods to Yemen. Before the war, Yemen imported nearly 90% of al food. Near Hudaydah, ships fil ed with food and fuel routinely sat off-shore, as Arab coalition vessels searched them for il icit arms.17 In order to implement the cargo inspection authority delineated in UNSCR 2216 and expedite the delivery of commercial goods while maintaining the arms embargo, the international community created a new inspections regime. In early 2016, the United Nations, at the request of the ROYG, established the U.N. Verification and Inspection Mechanism (UNVIM).18 UNVIM is a U.N.-led operation designed to inspect vessels sailing to Yemeni ports not under ROYG control for il icit weapons. UNVIM can inspect cargo, while also ensuring that commercial items are imported in a timely manner. Typical y, UNVIM processes clearance requests from commercial shippers. After reviewing each request, UNVIM decides to either: (1) not require inspection and grant vessel clearance; or (2) inspect the vessel in territorial or international waters based on suspicions of the vessel’s movements, crew, documents, or prohibited cargo. If prohibited items are found during an inspection, they are to be seized and disposed of by the Government of Djibouti in the presence of UNVIM Monitors. If a vessel fails to adhere to UNVIM procedures, standard operating procedure dictates that UNVIM wil contact the Saudi-led coalition’s Evacuation and Humanitarian Operation Cel (EHOC) at the Saudi Ministry of Defense. One chal enge to ensuring timely delivery of commercial goods to Yemen is that the ROYG and Saudi-led coalition employ an additional vessel clearance process subsequent to the UNVIM clearance. This “secondary” vessel clearance process occurs after UNVIM completes its due diligence. After UNVIM clears a vessel, it must proceed to what is referred to as the “Coalition Holding Area” or CHA off the coast of Saudi Arabia, where it must await permission from the ROYG and the EHOC to dock in Houthi-controlled Yemeni ports.19 Depending on the level of acrimony between the ROYG and the Houthis, the delay from this secondary clearance process can range from minimal to a serious impediment to the importation of products into Yemen. 17 “Arab Coalition Navy Inspections Paralyze Yemen Food Shipments,” Reuters, September 10, 2015, and “U.S. T ells U.N. it Wants to See Boost in Shipping into War-T orn Yemen,” Reuters, September 30, 2015. 18 For background, see United Nations, “In Hindsight: T he Story of the UN Verification and Inspection Mech anism in Yemen,” UN Security Council Report, September 2016. 19 T he United States has been working with ROYG and Saudi officials for several years to reduce the waiting time for vessels in the CHA. In a 2018 hearing on Yemen, a USAID official said, “We have been working very carefully—the State Department, USAID, other donors—with the coalition to reduce the time that the EHOC process—that is the coalition’s Evacuation Humanitarian Assistance Operations Cell. In the month of April 3 rd [2018], we got that down to about 3 to 4 days. So it is not 100 days. T here has been a lot of work done getting the communication between that process and the U.N. verification and inspection mechanism process together. T he U.N. system, UNVIM, gets back within 48 hours on a determination of whether or not a vessel actually needs to be searched or not, and then it goes through the EHOC process. We have seen, particularly in the last 6 weeks, significant progress on that, and we are looking forward to reducing those times even more. What we do need is we need shippers in the region to know how long it will take and that will, hopefully, get more shipping back into Hudaydah Port, particularly compartmentalized cargo.” T estimony of USAID Bureau for Democracy, Conflict, and Humanitarian Assistance Deputy Assistant Administrator Robert Jenkins, Senate Committee on Foreign Relations, U.S. Policy in Yemen, hearing, 115th Cong., 2nd sess., April 17, 2018, S.Hrg. 115-778 (Washington, DC: GPO, 2020). Congressional Research Service 6 Yemen: Civil War and Regional Intervention Earlier in 2021, a dispute between the ROYG and the Houthis led ROYG officials to deny clearance to fuel tankers, some of which lingered off the shores of Hudaydah port for months. This led to fuel price shortages and rising prices inside Yemen.20 According to a U.S. State Department spokesperson, the U.S. government opposes arbitrary restrictions of commodities entering Yemen, but respects “the right of the government to control its access to ports.”21 As of July 2021, USAID reported: Fuel shortages continue to contribute to sharp increases in fuel prices across Yemen, limiting access to essential services. The Republic of Yemen Government (RoYG) and the Kingdom of Saudi Arabia (KSA)-led Coalition approved four vessels carrying approximately 89,000 metric tons (MT) of fuel to discharge at Al Hudaydah Port—the primary entry point for fuel in northern Yemen—during June, according to the United Nations Verification and Inspection Mechanism for Yemen (UNVIM). UNVIM reports a 38 percent decrease in fuel discharged at Al Hudaydah in June 2021 compared with the average fuel discharged monthly in 2020; to date in 2021, fuel imports at Al Hudaydah are down by approximately 82 percent compared with the total amount of fuel imports at the port in 2020.22 In October 2021, the United Nations Security Council cal ed on the government of Yemen to: facilitate, regularly and without delay, the entry of fuel ships into Hudaydah port and emphasized the importance of all parties ensuring the free flow of fuel inside the country to deliver essential commodities and humanitarian aid, and underscored that fuel that arrives through Hudaydah port should not be used for personal profit or to fund escalation of the conflict. They urged the parties to work towards the stability of Hudaydah, including through cooperation with the United Nations Mission to Support the Hudaydah Agreement (UNMHA). They called for an end to the encirclement of Al‑Abdiyah.23 Failing Oil Tanker Moored off of Yemen’s west coast north of Hudaydah, the 44-year-old floating storage and offloading (FSO) Vessel Safer (owned by the state-run Yemen Oil and Gas Corporation) has been deteriorating for years. It holds an estimated 1.4 mil ion barrels of crude oil. Routine maintenance on the tanker stopped after the Saudi-led intervention began in March 2015. If the FSO Safer were to critical y fail, it would likely cause environmental damage within the Red Sea and would possibly put supplies of drinking water in danger due to its proximity to desalination plants. It could also force the port of Hudaydah to close for months, which would obstruct the supply of humanitarian aid to north Yemen. In order to assess the danger, the United Nations had been negotiating with the Houthis to permit a technical team access to the tanker. Although the Houthis had indicated that they would issue entry permits to U.N. inspectors, they have not given their final authorization. One U.N. spokesperson said that while the U.N. has committed $3.3 mil ion to begin work on the Safer, the Houthis may be reconsidering al owing them access.24 In October 2021, researchers from Stanford University, Harvard University, and UC Berkeley published research on the possible impact of an oil spil from the FSO Safer. According to their 20 Nima Elbagir and Angela Dewan, “First Fuel Ship this Year Docks in Hodeidah as Saudi-led Coalition Relaxes Blockade,” CNN, March 26, 2021. 21 “‘It is not a Blockade’: US says Saudi Arabia isn’t to Blame for Yemen’s Fuel Shortage,” Vox.com, April 14, 2021. 22 USAID, Yemen, Complex Emergency, Fact Sheet #6, July 16, 2021. 23 United Nations, Security Council Press Statement on Yemen, U.N. Document SC/14671, October 20, 2021. 24 Rick Gladstone, “ U.N. Delays Salvage of Yemen Oil T anker Amid Fears of Major Spill,” New York Times, February 2, 2021. Congressional Research Service 7 Yemen: Civil War and Regional Intervention model, a serious rupture of the FSO Safer would result in a spil that could lead to “nine mil ion [people] losing access to clean water and seven mil ion losing access to food supplies.”25 The Houthi-Saudi Arabia Conflict Since a Saudi-led coalition intervened on behalf of the ROYG in 2015, the Houthis and coalition forces have been engaged in what is referred to informal y as an air and missile war. The Saudis have conducted numerous air strikes in northern Yemen, while the Houthis have launched bal istic missiles and unmanned aerial vehicles (UAVs) into Saudi territory. As of 2021, reports of errant Saudi air strikes that have resulted in civilian
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As of March 2021, Special Envoy of the United Nations Secretary-General for Yemen Martin
Griffiths continues his efforts to broker a nation-wide cease-fire that would ultimately lead to
talks over a political settlement to Yemen’s regional and national conflicts. In recent weeks,
Griffiths has intensified his diplomatic outreach, traveling to various Gulf Arab states and Iran.
Perhaps the biggest obstacle to resolving the war is that the Houthis seek international recognition
of their de-facto authority in northern Yemen, a recognition of their legitimacy that neither
President Hadi nor the Saudi government appear ready to bestow.
On January 19, 2021, the Trump Administration designated the Houthis as a Foreign Terrorist
Organization (FTO) and a Specially Designated Global Terrorist (SDGT) entity. In notifying
Congress, then-Secretary of State Michael Pompeo identified that the Houthis were closely linked
to Iran and that the designations were intended to hold the Houthis accountable for terrorist acts.4
The designations reportedly had been under consideration for months, though aid organizations
repeatedly cautioned that designations would exacerbate what the United Nations presently
considers the world’s worst humanitarian crisis. On February 11, 2021, Secretary of State Antony
Blinken revoked the FTO and SDGT designations of the Houthis. The Secretary retained the
designations of five Houthi individuals as Specially Designated Nationals (SDN) under Executive
Order (E.O.) 13611. President Obama issued that order in 2012 to block property of persons
threatening the peace, security, or stability of Yemen. On March 2, the Biden Administration
designated two additional Houthi leaders under E.O 13611.5

4 U.S. Department of State, “Terrorist Designation of Ansarallah in Yemen,” Press Statement, Michael R. Pompeo,
Secretary of State, January 10, 2021.
5 U.S. Department of the Treasury, Office of Public Affairs, “Treasury Sanctions Key Military Leaders of the
Ansarallah Militia in Yemen,” Press Release, March 2, 2021.
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Figure 1. Lines of Control in Yemen
As of October 2020

Source: Graphic created by CRS using data from Risk Intelligence (2020); Esri (2017 & 2018); NOAA (2018);
USGS (2018); Department of State (2015).
Since March 2015, the U.S. military has supported Saudi-led coalition military operations in
Yemen, which have come under increasing scrutiny in Congress. However, on February 4, 2021,
President Biden announced that his Administration would increase U.S. efforts to resolve the
conflict in Yemen by: (1) appointing a special envoy to Yemen; (2) ending U.S. support for
offensive operations in the war, including relevant arms sales; and (3) continuing to help Saudi
Arabia defend its territory from Houthi attacks. According to one recent report, newly appointed
U.S. Special Envoy to Yemen Timothy Lenderking met with Houthi officials in Muscat, Oman, in
late February in order to press them to halt their military offensive in Marib (see below) and
engage Saudi Arabia in ceasefire negotiations.6

6 “U.S. Officials have Met Yemen's Houthis as Washington Seeks End to War: Sources,” Reuters, March 3, 2021.
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Figure 2. Lines of Control in Marib Governorate

Source: ACAPS, Yemen: Marib District Profiles, Thematic Report, February 19, 2021
The Houthi-ROYG War in the North: The Battle for Marib
As of early March 2021, Houthi forces continue to launch attacks against the forces of the
Republic of Yemen Government (ROYG) in Marib governorate. The Marib governorate is the last
northern stronghold of the ROYG. An estimated 800,000 internally displaced persons (IDPs),
who have fled conflict in other parts of the country, are located there.7 Marib also is the center of
Yemen’s modest hydrocarbon sector and, while the country imports over 90% of its oil and gas,
the oil refinery in Marib accounts for nearly 8% of Yemen’s total energy needs.8
The Houthis began offensive operations in Marib over a year ago. They escalated their attacks in
mid-February, perhaps in an effort to maximize their territorial gains in anticipation of renewed
international efforts, including by the Biden Administration, to broker a cease-fire to the conflict.
The Houthis may also be trying to consolidate their control over northern Yemen after the recent
implementation of the 2019 Riyadh Agreement, which brought the Southern Transition Council
(STC), a United Arab Emirates-backed southern Yemeni independence movement, into a unity
government with the ROYG. Though it is unlikely that the STC would commit fighters to defend
Marib, the Houthis may be pressing ahead now while the balance of power in northern Yemen is

7 United Nations Human Rights, Office of the High Commissioner, “Press briefing notes on Yemen,” February 19,
2021.
8 International Crisis Group, “Crisis in Marib: Averting a Chain Reaction in Yemen,” February 22, 2021.
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still in their favor. According to the International Organization for Migration, since January 2020,
140,000 Yemenis have fled from areas close to the frontlines in Marib and other governorates.9
Reports indicate that the Houthis have taken heavy casualties, as the front line remains
approximately 10-15 miles outside of Marib city (see Figure 2). While the Houthis have
advanced toward Marib city, military analysts suggest that their progress has been slowed. Saudi
Arabia continues to support ROYG ground forces with targeted air strikes. The terrain of Marib
city itself is relatively flat, which may further expose the Houthi ranks and make it more
challenging for their fighters, who are accustomed to fighting on mountainous terrain.10
Clashes Continue in Hudaydah
In December 2018, Special Envoy Griffiths brokered a cease-fire, known as the Stockholm
Agreement, centered on the besieged Red Sea port city of Hudaydah (also spelled Hodeidah, Al
Hudaydah, see Figure 1). More than two years later, the agreement remains unfulfilled and, as of
early March 2021, Houthi-ROYG clashes in Hudaydah continue. On March 1, the United Nations
Mission to Support the Hudaydah Agreement (UNMHA) condemned a mortar attack in the city
that killed five civilians. The United Nations did not attribute blame to a specific group and called
on the Houthis and the ROYG to abide by the terms of the ceasefire, prevent civilian casualties,
and allow U.N. monitors freedom of movement.11
Currently, the Houthis control the port and
city of Hudaydah itself, along with access to
Figure 3. U.N. Monitors in Hudaydah
the city from the north. To the south along the
Red Sea coast, a coalition of forces (dubbed
the “Joint Resistance Forces”) led by Tareq
Saleh, the nephew of the late former Yemeni
President Ali Abdullah Saleh, have remain
ensconced since 2018, when the Saudi-led
coalition attempted to seize Hudaydah from
the Houthis before the Stockholm Agreement
halted the fighting. Tareq Saleh’s forces are
based out of the port town of Mokha and
receive support from Saudi Arabia and the
United Arab Emirates. They are not formally
part of the ROYG and operate independently

from President Hadi.
Source: Twitter, U.N. Mission to support the

Hudaydah Agreement, October 15, 2020.
Failing Oil Tanker
Moored off of Yemen’s west coast north of Hudaydah, the 44-year-old floating storage and
offloading (FSO) Vessel Safer (owned by the state-run Yemen Oil and Gas Corporation) has been
deteriorating for years. It holds an estimated 1.4 million barrels of crude oil. Routine maintenance
on the tanker stopped after the Saudi-led intervention began in March 2015. If the FSO Safer
were to critically fail, it would likely cause environmental damage within the Red Sea, but would

9 IOM Yemen, “Displacement in Marib,” Flash Update, February 23, 2021.
10 Michael Horton, “Yemen’s Fate Hinges on The Battle for Marib,” The Jamestown Foundation, Terrorism Monitor,
Volume: 19 Issue: 4, February 26, 2021.
11 “Yemen: U.N. Ceasefire Monitoring Mission Condemns Attack on Civilians in Hudaydah,” U.N. News, March 1,
2021.
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possibly put supplies of drinking water in danger due to its proximity to desalination plants. It
could also force the port of Hudaydah to close for months, adding delay to the supply of
humanitarian aid to north Yemen. In order to assess the danger, the United Nations had been
negotiating with the Houthis to permit a technical team access to the tanker. Although the Houthis
had indicated that they would issue entry permits to U.N. inspectors, they have not given their
final authorization. One U.N. spokesperson said that while the U.N. has committed $3.3 million
to begin work on the Safer, the Houthis may be reconsidering allowing them access.12
The Houthi-Saudi Arabia Conflict
Since a Saudi-led coalition intervened on behalf of the ROYG in 2015, the Houthis and coalition
forces have been engaged in what is referred to informally as an air or missile war. The Saudis
have conducted numerous air strikes in northern Yemen, while the Houthis have launched
ballistic missiles and unmanned aerial vehicles (UAVs) into Saudi territory. As of early March
2021, reports of errant Saudi air strikes that have resulted in civilian casualties continue, though casualties continue, though
far less frequently than in earlier periods of the warfar less frequently than in earlier periods of the war (see Figure 4). The Yemen Data Project, a . The Yemen Data Project, a
non-profit independent data collection project, has non-profit independent data collection project, has tallied over 22,700tal ied over 23,627 Saudi-led coalition air Saudi-led coalition air
strikes since March 2015, strikes since March 2015, resulting in over 18,resulting in over 18,500600 civilian casualties.26 While the Houthis do not possess manned aircraft, they have conducted persistent bal istic missile and UAV launches against Saudi territory in a campaign they now describe as a response to the Saudi-led coalition’s ongoing maritime blockade of Yemen’s west coast and closure of Sana’a airport. In September 2021, Secretary of State Blinken condemned an attack against the Eastern Province of Saudi Arabia that injured two children and damaged several homes.27   25Abubakr Al Shamahi, “‘Looming Disaster’: Oil Ship Leak T hreatens Millions of Yemenis,” Al Jazeera English, October 11, 2021. See also, Benjamin Q. Huynh et al., “ Public Health Impacts of an Imminent Red Sea Oil Spill,” Nature Sustainability, (2021), October 11, 2021, and Janelle Weaver, “ Anticipated Spill from Deteriorating Red Sea Oil T anker T hreatens Public Health, Stanford-led Study Finds,” Stanford School of Medicine, October 11, 2021. 26 Yemen Data Project, Air War Dataset, available online at https://yemendataproject.org/data.html. 27 U.S. Department of State, T he United States Condemns Houthi Attack Against Saudi Arabia, Press Statement, Antony J. Blinken, Secretary of State, September 5, 2021. Congressional Research Service 8 Yemen: Civil War and Regional Intervention Figure 4. Saudi-led Coalition Air Strikes per Month Source: Yemen Data Project, November 2021. Peace Efforts Stall Throughout 2021, various third parties, including special envoys from the United Nations and United States as wel as Omani officials, have attempted to work in concert in order to reach a cease-fire between the Houthis and the Saudi-led coalition. These efforts have coincided with a separate track of talks hosted by the Iraqi government between high level Saudi and Iranian officials, reportedly aimed at deescalating regional tensions in various locales, including Yemen.28 In March 2021, Saudi Arabia offered a nationwide ceasefire that was praised by U.S. officials.29 Specifical y, Saudi Foreign Minister Prince Faisal bin Farhan proposed that, if the Houthis agreed to a nationwide ceasefire under U.N. supervision, Saudi Arabia would (1) adhere to a U.N.- supervised ceasefire, (2) reopen Sana'a International Airport to direct flights, (3) al ow fuel into Hudaydah port with revenues deposited in a joint Houthi-ROYG bank account, and (4) restart political negotiations for a permanent settlement to the conflict. The Houthis almost immediately dismissed the Saudi proposal as “nothing new” and reiterated their demands for the Saudis unilateral y to lift their blockade of Sana'a airport and Hudaydah port.30 28 “Iran-Saudi T alks have Gone a ‘Good Distance’ – Iran’s Foreign Minister,” Reuters, October 7, 2021. 29 U.S. Department of State, Briefing on Yemen with T imothy Lenderking, U.S. Special Envoy for Yemen; and Sarah Charles, USAID Assistant Administrator for Humanitarian Assistance, August 9, 2021. 30 Reuters, “Houthis say nothing new in Saudi peace offer, will keep talking,” March 22, 2021. Congressional Research Service 9 Yemen: Civil War and Regional Intervention In late summer 2021, Swedish diplomat Hans Grundberg became the U.N. Special Envoy for Yemen. Upon taking office, Grundberg acknowledged the difficult path toward brokering peace in Yemen, saying “The conflict parties have not discussed a comprehensive settlement since 2016.... It is therefore long overdue for the conflict parties to engage in peaceful dialogue with one another under U.N. facilitation on the terms of an overarching settlement, in good faith and without preconditions.”31 As of November 2021, the Houthis have continued to demand that the coalition agree to lift restrictions on access to airports and ports in northern Yemen prior to any ceasefire agreement. With the Houthis continuing to advance on multiple fronts throughout Yemen, many observers doubt that third-party mediation wil result in any diplomatic breakthroughs. According to Peter Salisbury of the International Crisis Group, “From an Iranian perspective, their al y in Yemen the Houthis appear very close in effect to winning the war in the north, if not the entire country. It is extremely difficult to understand why they or the Houthis would feel this is the right moment to stop.”32 Iranian Support to the Houthis Iranian knowledge transfer and military aid to the Houthis, in violation of UNSCR 2216, has increased the Houthis’ ability to threaten Saudi Arabia, other Gulf nations, and waters adjacent to Yemen. According to the U.N. Panel of Experts on Yemen, “An increasing body of evidence suggests that individuals or entities in the Islamic Republic of Iran supply significant volumes of weapons and components to the Houthis.”33 The United States, the United Kingdom, Israel, and Saudi Arabia al have offered evidence throughout 2021 of extensive Iranian military involvement in Yemen. In April 2021, Iran acknowledged that one of its vessels in the Red Sea had been attacked. Subsequent reports suggested that Israel may have attacked the MV Saviz, a suspected Islamic Revolutionary Guard Corps floating base used, according to Saudi sources, to conduct surveil ance and facilitate weapons transfers into Yemen.34 In May 2021, the U.S. Navy announced that the guided-missile cruiser USS Monterey intercepted a stateless dhow in the northern reaches of the Arabian Sea. After sailors boarded it, they uncovered 3,000 Chinese Type 56 assault rifles, hundreds of other heavy machine guns, sniper rifles, and dozens of advanced, Russian-made anti-tank guided missiles.35 In September 2021, Israel identified an Iranian base (Kashan Base north of Esfahan) used to train foreign militants, including the Houthis, on drone technology.36 In October 2021, a 31 Edith M. Lederer, “New UN envoy: Yemen is stuck in `indefinite state of war,'” Associated Press, September 10, 2021. 32 Mohammed Ghobari and Ghaida Ghantous, “Yemen's Marib City Battens Down as Houthis Advance T hrough Energy-Rich Province,” Reuters, November 2, 2021. 33 See United Nations Panel of Experts on Yemen, “Letter dated 22 January 2021 from the Panel of Experts on Yemen addressed to the President of the Security Council,” U.N. Document S/2021/79, January 25, 2021. 34 Jon Gambrell, “Iran Ship said to be Red Sea T roop Base off Yemen Attacked,” Associated Press, April 7, 2021. 35 Jon Gambrell, “US Navy seizes Arms Shipment in Arabian Sea likely bound for Yemen,” Associated Press, May 9, 2021. 36 Jeremy Binnie, “Israeli Defence Minister Identifies Iran’s UAV T raining Base for Foreigners,” Jane’s Defence Weekly, September 14, 2021. Congressional Research Service 10 civilian casualties.13 Another monitoring
organization, The Civilian Impact Monitoring Project (CIMP), a service under the United Nations
Protection Cluster for Yemen, recorded 2,087 civilian casualties in 2020 (749 people killed and
1,338 injured), a decrease from 3,224 civilian casualties in 2019 (1,104 deaths and 2,120
injuries), and from 4,934 in 2018 (2,049 deaths and 2,885 injuries).14
While the Houthis do not possess manned aircraft, they have conducted persistent ballistic missile
and UAV launches against Saudi territory in an ongoing campaign they claim is in response to the
Saudi-led coalition’s ongoing maritime blockade of Yemen’s west coast and closure of Sana'a
airport. In February 2021, a Houthi drone attack against Abha Airport in southern Saudi Arabia
struck a civilian plane, though no casualties were reported. Secretary of State Blinken condemned
the attack.15 In addition to aerial bombardment, the Houthis also have targeted vessels transiting
the Red Sea or berthed in Saudi ports.16

12 Rick Gladstone, “U.N. Delays Salvage of Yemen Oil Tanker Amid Fears of Major Spill,” New York Times, February
2, 2021.
13 Yemen Data Project, Air War Dataset, available online at https://yemendataproject.org/data.html.
14 United Nations Office for the Coordination of Humanitarian Affairs, “Yemen Humanitarian Update, Issue 1, January
2021,” February 12, 2021.
15 U.S. Department of State, Office of the Spokesperson, “Secretary Blinken’s Call with Saudi Foreign Minister Faisal
bin Farhan Al Saud,” Readout, February 10, 2021.
16 “FACTBOX-Attacks, Incidents on Ships and Oil Around Saudi Arabia,” Reuters, December 14, 2020.
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Figure 4. Saudi-led Coalition Air Strikes Per Month

Source: Yemen Data Project, February 2021
Yemen: Civil War and Regional Intervention report prepared for the British government found that Iran has used a network of global commercial companies to procure components for Houthi arms.37 Missile and drone attacks perpetrated by Iran and Iran-supported militant groups represent a significant threat inside and outside of Yemen. Iran has supplied Yemen-based Houthis and other regional proxy groups with weapons to conduct destructive and sometimes lethal attacks using drones, missiles, and rockets against a variety of Saudi sites, including critical infrastructure, civilian airports, military bases, and energy facilities throughout the country, as wel as vessels in Red Sea shipping lanes. Recent attacks were aimed at targets throughout Saudi Arabia including Riyadh, Jeddah, Dhahran, Jizan, Khamis Mushayt, the civilian airport in Abha, Al Kharj, and military instal ations in the south, as wel as oil and gas facilities. Debris from intercepted drones and missiles represents a recurrent risk to civilian areas and populations.38 In October 2020, Iran appointed Hassan Eyrlo (alt. sp. Irlu) as Ambassador to the so-cal ed “National Salvation Government,” the Houthi-run northern Yemeni authority. The appointment made Iran the first country to recognize the Houthis diplomatical y as a legitimate government since they seized control of the capital city of Sana’a in 2014. On December 8, 2020, under the authority of Executive Order 13224, the U.S. Department of the Treasury’s Office of Foreign Asset Control (OFAC) designated Hassan Eyrlo as a Special y Designated National (SDN) due to his position as an “official in Iran’s Islamic Revolutionary Guard Corps-Qods Force (IRGC-QF) and the Iranian regime’s envoy to the Houthi rebels in Yemen.”39 Eyrlo attended a January 2021 vigil in Sana’a to mark the one-year anniversary of the U.S. kil ing of former IRGC-QF Commander Qassem Soleimani. Southern Yemen: Tentative Unity between the ROYG and STC
In December 2020, the UAE-backed Southern Transitional Council (STC) In December 2020, the UAE-backed Southern Transitional Council (STC) formallyformal y joined a unity joined a unity
government with the ROYG, ending several years of clashes in Aden between southern government with the ROYG, ending several years of clashes in Aden between southern
separatists and forces loyal to President Hadi. Saudi Arabia brokered the formation of the unity separatists and forces loyal to President Hadi. Saudi Arabia brokered the formation of the unity
government after over a year of STC-ROYG negotiations that followed the two sides’ government after over a year of STC-ROYG negotiations that followed the two sides’
commitment to cooperate as part of the November 2019 Riyadh Agreement. Under their unity commitment to cooperate as part of the November 2019 Riyadh Agreement. Under their unity
arrangement, the STC received several cabinet positions and agreed to redeploy their military arrangement, the STC received several cabinet positions and agreed to redeploy their military
forces from Abyan and Aden. On December 30, 2020, as the new members of the government forces from Abyan and Aden. On December 30, 2020, as the new members of the government
landed at Aden airport to assume their posts, the Houthis launched a coordinated missile attack landed at Aden airport to assume their posts, the Houthis launched a coordinated missile attack
against the airport, which against the airport, which killedkil ed 25 people, including three members of the International Red 25 people, including three members of the International Red
Cross.Cross.1740
While the UAE While the UAE formally formal y withdrew its main military contingent from Yemen in 2019, it has withdrew its main military contingent from Yemen in 2019, it has
retained a retained a small smal military presence while working with proxies throughout southern Yemen, most notably the STC. In 2021, there have been several reports al eging that the UAE, either 37 Benoit Faucon and Dion Nissenbaum, “Iranian Drones Reshape Mideast Security,” Wall Street Journal, October 7, 2021. 38 U.S. Department of State, Saudi Arabia T ravel Advisory, September 17, 2019 . 39 U.S. Department of the T reasury, “ Treasury Sanctions Iran’s Envoy in Yemen and University Facilitating Recruitment for Qods Force,” Press Release, December 8, 2020. 40 International Committee of the Red Cross, “Yemen: T hree ICRC Staff Members Killed in Airport Blast,” December 30, 2020. Congressional Research Service 11 Yemen: Civil War and Regional Intervention unilateral y or through local proxies, has been constructing infrastructure or asserting influence on the Red Sea volcanic island of Mayun and in the Socotra archipelago, both of which are strategical y located in the Arabian Sea-Bab al Mandeb corridor.41 military presence while working with proxies throughout southern Yemen, most
notably the STC. According to the United Nations Panel of Experts on Yemen, “The United Arab According to the United Nations Panel of Experts on Yemen, “The United Arab
Emirates is a member of the Coalition to Restore Legitimacy in Yemen, yet its support to the Emirates is a member of the Coalition to Restore Legitimacy in Yemen, yet its support to the
Southern Transitional Council undermines the Southern Transitional Council undermines the Government of Yemen.”42 As the Houthis advance into Yemen’s southern provinces, such as Shabwa, home to the Balhaf Liquefied Natural Gas Facility,43 their presence is exacerbating tensions between the STC and ROYG.44 Fighting in Marib governorate displaced units affiliated with the Islamist political movement Al Islah to Shabwa, placing them in close proximity to the STC, which the latter claims is a violation of the Riyadh Agreement.45 Biden Administration Policy After President Biden took office, one of his first foreign policy priorities was to review the previous Administration’s recent actions on Yemen. On February 4, 2021, President Biden announced that his Administration would increase U.S. efforts to resolve the conflict in Yemen by (1) appointing a special envoy to Yemen; (2) ending U.S. support for offensive operations in the war, including relevant arms sales; and (3) continuing to help Saudi Arabia defend its territory from Houthi attacks. A week later, Secretary of State Antony Blinken revoked the previous Administration’s January 2021 designations of the Houthis as a Foreign Terrorist Organization (FTO) and Special y Designated Global Terrorists (SDGTs).46 The Secretary retained the designations of three Houthi individuals as SDNs under Executive Order (E.O.) 13611.47 President Obama issued that order in 2012 to block property of persons threatening the peace, security, or stability of Yemen. On March 2, the Biden Administration designated two additional Houthi leaders under E.O. 13611.48 Since the President’s February 2021 policy pronouncement on Yemen, the United States has ceased support to offensive operations by Saudi Arabia and its coalition partners and made some changes to U.S. missile and air defense posture in Saudi Arabia. In April 2021, CENTCOM Commander General Kenneth F. McKenzie, Jr. told one reporter that in Marib, “We’re not doing 41 For example, see Jon Gambrell, “Mysterious Air Base Being Built on Volcanic Island off Yemen,” Associated Press, May 25, 2021; and, Quentin Muller, “UAE Wants Control of the Gulf of Aden; T ensions Mount over Yemen’s Contested Islands,” Le Monde diplom atique, September 2021. 42 See Government of Yemen.”18

17 International Committee of the Red Cross, “Yemen: Three ICRC Staff Members Killed in Airport Blast,” December
30, 2020.
18 See United Nations Panel of Experts on Yemen, “Letter dated 22 January 2021United Nations Panel of Experts on Yemen, “Letter dated 22 January 2021 from the Panel of Experts on Yemen from the Panel of Experts on Yemen
addressedaddressed to the President of the Security Council,” S/2021/79, January 25, 2021. 43 Several key foreign investors are involved in natural gas production in Yemen. For Balhaf, the French company T otal SA has a 39.6% interest alongside U.S.-based Hunt Oil (17.2%); South Korea’s SK Innovation, and Hyundai and Kogas (a combined 21.4%). 44 In Yemen, the tribal/Sunni Islamist movement known as Al Islah (Reform) has been a major player in national politics for decades and, since the Houthi offensive in 2014, it aligned itself with the ROYG and Saudi Arabia. In order to counter the ROYG-Saudi-Islah alliance, the UAE chose to align itself with southern separatists. 45 “Separatists and Islamists Vie for Power in Southern Yemen,” Economist Intelligence Unit – ViewsWire, October 27, 2021. 46 U.S. Department of State, Revocation of the T errorist Design ations of Ansarallah, Press Statement, Antony J. Blinken, Secretary Of State, February 12, 2021. 47 Ibid., U.S. Department of State, February 12, 2021. 48 U.S. Department of the T reasury, Office of Public Affairs, “T reasury Sanctions Key Military Leaders of the Ansarallah Militia in Yemen,” Press Release, March 2, 2021. to the President of the Security Council,” S/2021/79, January 25, 2021.
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Iranian Support to the Houthis
Iranian knowledge transfer and military aid to the Houthis, in violation of the targeted
international arms embargo (U.N. Security Council Resolution 2216), has increased the Houthis’
ability to threaten Saudi Arabia and other Gulf nations. According to the United Nations Panel of
Experts on Yemen, “An increasing body of evidence suggests that individuals or entities in the
Islamic Republic of Iran supply significant volumes of weapons and components to the
Houthis.”19
In October 2020, Iran appointed Hassan Eyrlo (alt. sp. Irlu) as Ambassador to the so-called
“National Salvation Government,” the Houthi-run northern Yemeni authority. The appointment
made Iran the first country to diplomatically recognize the Houthis as a legitimate government
since they seized control of the capital city of Sana’a in 2014. On December 8, 2020, under the
authority of E.O.13224, the U.S. Treasury Department’s Office of Foreign Asset Control (OFAC)
designated Hassan Eyrlo as a Specially Designated National (SDN) due to his position as an
“official in Iran’anything in terms of ISR (intel igence, surveil ance, and reconnaissance) … on things happening in Marib or places like that.”49 Nevertheless, Administration officials have reiterated U.S. support for Saudi Arabia's territorial defense. In April 2021 testimony before the House Armed Services Committee, Amanda Dory, Acting Under Secretary of Defense for Policy, stated: Our second line of effort is to provide limited, non-combat support to the Saudi-led Coalition (SLC) focused on defending Saudi Arabia from external threats. This non-combat support is consistent with President Biden's February 4, 2021 announcement to increase U.S. diplomatic efforts to end the war in Yemen and cease U.S. support to SLC offensive operations in Yemen. Continued U.S. assistance is designed to reassure U.S. partners of our commitment to their defense so that they can meaningfully engage in the United Nations political process to end the war. In support of the President's policy, roughly 60 DoD military advisors are deployed to help Saudi Arabia's Armed Forces defend their territory from threats emanating from Yemen.50 In June 2021, President Biden reported to the Congress that: A small number of United States military personnel are deployed to Yemen to conduct operations against al-Qa’ida in the Arabian Peninsula and ISIS. The United States military continues to work closely with the Government of the Republic of Yemen and regional partner forces to degrade the terrorist threat posed by those groups. I have directed an end to United States support for the Saudi‑led Coalition’s offensive military operations against the Houthis in Yemen. United States Armed Forces, in a non‑combat role, continue to provide military advice and limited information to regional forces for defensive and training purposes only as they relate to the Saudi-led Coalition’s campaign against the Houthis in Yemen. Such support does not involve United States Armed Forces in hostilities with the Houthis for the purposes of the War Powers Resolution. United States Armed Forces are deployed to the Kingdom of Saudi Arabia to protect United States forces and interests in the region against hostile action by Iran or Iran-backed groups. These forces, operating in coordination with the Government of the Kingdom of Saudi Arabia, provide air and missile defense capabilities and support the operation of United States fighter aircraft. The total number of United States forces in the Kingd om of Saudi Arabia is approximately 2,742.51 By summer 2021, with little progress toward peace negotiations, the Biden Administration had become more openly critical of the Houthis for rejecting repeated attempts at brokering a cease-fire while continuing their ground offensive in Yemen and their aerial assaults against civilian targets inside Saudi Arabia.52 Throughout 2021, the Biden Administration has continued to use its authority to sanction individual Houthi leaders who have obstructed Yemen’s stability.53 In May 2021, the Biden Administration, pursuant to Executive Order 13611, designated two senior 49 “US-Made Drones Downed over Yemen weren't Military’s, CENT COM says,” Al Monitor, June 24, 2021. 50 T estimony of Amanda Dory, Acting Under Secretary of Defense for Policy, Department of Defense, Hearing entitled, “ National Security Challenges and U.S. Military Activities in the Greater Middle East and Africa, ” House Armed Services Committee, April 20, 2021. 51 T he White House, Letter to the Speaker of the House and President Pro T empore of the Senate Regarding the War Powers Report, June 8, 2021. 52 See, U.S. Department of State, Department Press Briefing, July 1, 2021 and United States Mission to the United Nations, Ambassador Richard Mills, U.S. Deputy Representative to the United Nations, New Y ork, NY, September 10, 2021. 53 Pursuant to, inter alia, the International Emergency Economic Powers Act (50 U.S.C. §§1701 et seq.) and the National Emergencies Act (50 U.S.C. §§1601 et seq.). T he President has extended the national emergency declared in Executive Order 13611 of May 16, 2012, with respect to Yemen to continue in effect beyond May 16, 2021. See, Congressional Record, House Executive Communications, Page H2183, May 11, 2021, Continuation of the National Emergency with Respect to Yemen--Message from the President of the United States (H. Doc. No. 117 -37). Congressional Research Service 13 Yemen: Civil War and Regional Intervention Houthis leaders as SDNs for their role in the offensive against Marib.54 On June 10, 2021, under the authority of Executive Order 13224, the Treasury Department designated several members of a smuggling network that “helps fund Iran's Islamic Revolutionary Guard Corps-Qods Force s Islamic Revolutionary Guard Corps-Qods Force (IRGC-QF) and the Houthis in Yemen.”55 In November 2021, the Administration designated Saleh Mesfer Alshaer, the commander of the Houthi-controlled military logistics organization, as an SDN for smuggling weapons and misappropriating state funds designated for hospitals.56 Houthis Storm U.S. Embassy In early November 2021, Houthi gunmen entered the U.S. Embassy in Sana’a, where they captured 39 local Yemeni staff who maintain the compound. The U.S. State Department and Members of Congress immediately denounced the action and cal ed on the Houthis to release al personnel.57 According to the State Department, “The Houthis’ unprovoked abuse of these Yemeni citizens is a gross disregard of diplomatic norms, as is the Houthis’ flagrant breach of the compound used by the U.S. Embassy prior to 2015.”58 Several weeks later, most employee who were kidnapped were released, though as of November 23, several remain in Houthi custody. On February 11, 2015, due to the deteriorating security situation in Sana’a, the State Department suspended embassy operations and U.S. Embassy staff was relocated to Saudi Arabia. Since then, the embassy has been primarily maintained and protected by local Yemeni employees. As of early November 2021, the Administration has continued to single out the Houthis as the primary party responsible for perpetuating conflict. According to U.S. State Department Spokesperson Ned Price, “The Houthis, despite their claims to the contrary, have been a primary cause of the hardship that the people of Yemen face today. There have been credible proposals put on the table, proposals that the Republic of Yemen Government, proposals that Saudi authorities have also been behind that – on which the Houthis have so far been unwil ing to engage.”59 (IRGC-QF) and the Iranian
regime’s envoy to the Houthi rebels in Yemen...”20 Eyrlo attended a January 2021 vigil in Sana’a
to mark the one-year anniversary of the U.S. killing of former IRGC-QF Commander Qassem
Soleimani.
Yemen’s Humanitarian Crisis
The United Nations has described Yemen’s humanitarian crisis as currentlyThe United Nations has described Yemen’s humanitarian crisis as currently one of the worst in the the worst in the
world, with close to 80% of Yemen’s population of nearly 30 world, with close to 80% of Yemen’s population of nearly 30 million mil ion needing some form of needing some form of
assistance. In Yemen, myriad factors (e.g., war, loss of health services, funding shortages, assistance. In Yemen, myriad factors (e.g., war, loss of health services, funding shortages,
currency depreciation) have combined to put the most vulnerable populations at risk. According currency depreciation) have combined to put the most vulnerable populations at risk. According
to various United Nations agencies, acute malnutrition among children under the age of five in to various United Nations agencies, acute malnutrition among children under the age of five in
Yemen has hit the highest levels ever recorded; nearly 2.3 Yemen has hit the highest levels ever recorded; nearly 2.3 millionmil ion children under age 5 in Yemen children under age 5 in Yemen
are at risk of acute malnutrition in 2021.are at risk of acute malnutrition in 2021.21
Food Insecurity & Humanitarian Access
While the international community has not officially declared a famine in Yemen, food insecurity
amongst large swaths of the population is increasing (see Figure 5). According to the December
2020 United Nations’ Integrated Food Security Phase Classification (IPC) projections for Yemen,
54% of the population (16.2 million) may experience high levels of acute food insecurity in the
first half of 2021. Out of these, U.N. projections indicate an estimated 11 million people will
likely be in crisis (IPC Phase 3), 5 million in Emergency (IPC Phase 4), and 47,000 in
Catastrophe (IPC Phase 5, famine-like conditions).22
Humanitarian workers have long documented the numerous challenges to working in Yemen,
such as lack of access to areas in need of assistance. As Yemen has devolved into various centers
of power, aid agencies have had to navigate competing rules and regulations between northern

19 Op.cit.., Panel of Experts on Yemen.
20 U.S. Department of the Treasury, “Treasury Sanctions Iran’s Envoy in Yemen and University Facilitating
Recruitment for Qods Force,” Press Release, December 8, 2020.
21 United Nations Office for the Coordination of Humanitarian Affairs, Yemen Situation Report, February 14, 2021.
22 Integrated Food Security Phase Classification (IPC), “Yemen: Acute Food Insecurity Situation October - December
2020 and Projection for January - June 2021.”
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and southern Yemen and sometimes within individual governorates. According to one account,
“Institutional overlap between rival governments has created numerous logistical issues, such as
humanitarian workers needing to obtain duplicate visas and permits from multiple ministries.”23
Figure 5. World Food Programme: Emergency Dashboard Yemen
January 2021

Source: World Food Programme, Yemen Emergency Dashboard January 2021, updated February 2021.
As the Houthis have become further ensconced in northern Yemen and placed key members in
positions of authority, Houthi restrictions on humanitarian aid agencies working in northern
Yemen have grown more onerous.24 Control and diversion of aid is one means Houthi forces,
Houthi partners, and other parties to the conflict have used to finance their operations.25

23 Jan Egeland, Alex Harper, Emma Beals, and Jomana Qaddour60 Over 10,000 children have been kil ed or injured in 54 U.S. Department of the T reasury, "Treasury Sanctions Senior Houthi Military Official Overseeing Group's Offensive Operations," press release, May 20, 2021. 55 U.S. Department of the T reasury, "Treasury Sanctions Network Financing Houthi Aggression and Instability in Yemen," press release, June 10, 2021. 56 U.S. Department of State, Designation of Houthi Official in Yemen, Press Statement , Antony J. Blinken, Secretary of State, November 19, 2021. 57 See, McCaul, Meeks, Risch, Menendez Joint Statement on Houthi Breach of U.S. Embassy in Yemen, Press Release, November 12, 2021. 58 U.S. State Department, T he United States Condemns the Houthi Detention of Yemeni Staff of the U.S. Embassy in Sana’a and Breach of Embassy Compound, Press Statement, Antony J. Blinken, Secretary of State, November 19, 2021. 59 U.S. Department of State, Department Press Briefing, November 3, 2021. 60 United Nations Office for the Coordination of Humanitarian Affairs, Yemen Situation Report, February 14, 2021. Congressional Research Service 14 link to page 19 Yemen: Civil War and Regional Intervention Yemen since 2015; currently 4 in 5 children are in need of humanitarian assistance, 400,000 are suffering from severe acute malnutrition, and 2 mil ion are out of school.61 Food Insecurity & Humanitarian Access While the international community has not official y declared a famine in Yemen, food insecurity amongst large swaths of the population is widespread (see Figure 5). According to the World Food Program in October 2021, 16.2 mil ion people are food insecure, and 47,000 face famine-like conditions.62 While the conflict continues to be the main driver of food insecurity across the country, a worsening economic crisis in the form of rising prices and an increasingly high exchange rate in southern Yemen is creating additional burdens for many Yemenis.63 Humanitarian workers have long documented the numerous chal enges to working in Yemen, such as lack of access to areas in need of assistance. As Yemen has devolved into various centers of power, aid agencies have had to navigate competing rules and regulations between northern and southern Yemen and sometimes within individual governorates. According to one account, “Institutional overlap between rival governments has created numerous logistical issues, such as humanitarian workers needing to obtain duplicate visas and permits from multiple ministries.”64 As the Houthis have become further ensconced in northern Yemen and placed key members in positions of authority, Houthi restrictions on humanitarian aid agencies working in northern Yemen have grown more onerous.65 Control and diversion of aid is one means Houthi forces, Houthi partners, and other parties to the conflict have used to finance their operations.66 In 2020, as international frustration over Houthi obstruction of humanitarian assistance mounted, the international community warned that if the Houthis do not abide by the principles of international humanitarian law and al ow for unimpeded access for humanitarian assistance, they wil risk losing aid. In March 2020, USAID initiated a partial suspension of its funding to support humanitarian operations in northern Yemen. The suspension followed several weeks of warnings from U.S. officials that the Trump Administration was extremely concerned over Houthi obstruction of aid.67 The Biden Administration lifted the suspension in March 2021,68 and in September announced nearly $291 mil ion in additional humanitarian assistance for Yemen as “ongoing hostilities, a deepening economic crisis, acute food insecurity, and the spread of COVID-19 continue to generate humanitarian needs in the country.”69 61 UN News, “ Yemen war reaches ‘shameful milestone’ - 10,000 children now killed or maimed,” October 19, 2021. 62 World Food Programme, “ Yemen Situation Report #9, September 2021,” October 18, 2021. 63 USAID, “Yemen – Complex Emergency, Fact Sheet #8, Fiscal Year (FY) 2021” September 23, 2021. 64 Jan Egeland et al., “Humanitarian Aid and the Biden Administration: , “Humanitarian Aid and the Biden Administration:
Lessons from Yemen and Syria,” Policy Forum Lessons from Yemen and Syria,” Policy Forum Report, The Washington InstituteReport , T he Washington Institute for Near East Policy, January 25, 2021. , January 25, 2021.
24 65 According to senior U.N. officials, Houthi obstructions include: According to senior U.N. officials, Houthi obstructions include: obstacles to beneficiary registration, attempts to obstacles to beneficiary registration, attempts to
divert aid, efforts to control selection of implementing partners, detention and arrest of divert aid, efforts to control selection of implementing partners, detention and arrest of humanitarianh umanitarian workers, and workers, and
intimidation and harassmentintimidation and harassment of aid workers at of aid workers at Sana’a Sanaa airport. See Under-Secretary-General for Humanitarian Affairs airport. See Under-Secretary-General for Humanitarian Affairs
and Emergency Relief Coordinator Mark Lowcock, “Briefing to the Security Council on the Humanitarian Situation in and Emergency Relief Coordinator Mark Lowcock, “Briefing to the Security Council on the Humanitarian Situation in
Yemen - As Delivered,” NewYemen - As Delivered,” New York, NY, September 16, 2019. See also “York, NY, September 16, 2019. See also “ UN: Houthi RebelsUN: Houthi Rebels Impeding AidImpeding Aid Flow Flow in in
Yemen,” Yemen,” Al Jazeera English, February 19, 2020. , February 19, 2020.
2566 Sam Sam Kiley, SarahKiley, Sarah El SirganyEl Sirgany , and Brice Lainé, “CNN exposes systematic abuse of aidand Brice Lainé, “CNN exposes systematic abuse of aid in Yemen,” in Yemen,” CNN, CNN, May 20, 2019. 67 Ambassador Kelly Craft, “ Remarks at a U.N. Security Council Briefing on the Situation in Yemen,” U.S. Mission to the United Nations, February 18, 2020. 68 Katrina Mason, “ US resumes aid to rebel-controlled regions of Yemen,” Financial Times, March 11, 2021. 69 USAID, “Yemen – Complex Emergency, Fact Sheet #8, Fiscal Year (FY) 2021” September 23, 2021. Congressional Research Service 15 Yemen: Civil War and Regional Intervention Figure 5. World Food Programme: Emergency Dashboard Yemen August 2021 Source: World Food Programme, Yemen Emergency Dashboard August 2021, updated September 2021. The COVID-19 Pandemic in Yemen The COVID-19 pandemic has added an additional layer of concern for Yemen’s already depleted health system. Data from the World Health Organization from November 2021 indicate a total of 9,806May 20,
2019.
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In 2020, as international frustration over Houthi obstruction of humanitarian assistance mounted,
the international community warned that if the Houthis do not abide by the principles of
international humanitarian law and allow for unimpeded access for humanitarian assistance, they
will risk losing aid. In March 2020, USAID initiated a partial suspension of its funding to support
humanitarian operations in northern Yemen. The suspension followed several weeks of warnings
from U.S. officials that the Trump Administration was extremely concerned over Houthi
obstruction of aid.26
As of March 2021, USAID has continued its partial suspension of $50 million in humanitarian
programming in Houthi-controlled areas of Yemen due to continued “Houthi-imposed
bureaucratic impediments.” USAID continues to fund more than $13 million in humanitarian
NGO activities in northern Yemen for programs that can be conducted without Houthi
interference.27
The COVID-19 Pandemic in Yemen
The COVID-19 pandemic has added an additional layer of concern for Yemen’s already depleted
health system. U.N. statistics from December 2020 indicate a total of 2,103 COVID-19 cases with
611 COVID-19 cases with 1,894 deaths; most health experts believe that these figures vastly underestimate the extent of deaths; most health experts believe that these figures vastly underestimate the extent of
COVID-19 in Yemen.28COVID-19 in Yemen.70 Nearly 550,000 vaccine doses have been administered in the country.71 A delivery of approximately 151,200 doses of Johnson & Johnson COVID-19 vaccines provided by USAID through COVAX, the global COVID-19 vaccination distribution program arrived in August 2021, as the country was beginning to witness a third wave of cases in September-October 2021. Yemen previously received 360,000 AstraZeneca vaccines in March through COVAX, and the United States has agreed to provide an additional 350,000 doses through COVAX. 72 The United Nations has procured medical equipment, testing kits, and The United Nations has procured medical equipment, testing kits, and
medicine while seeking additionalmedicine while seeking additional supplies. Aid groups also have increased the capacity 70 United Nations, COVID-19 Preparedness and Response Monthly Report, December 2020. 71 World Health Organization, “COVID-19 Dashboard,” accessed November 4, 2021. 72 USAID, “Yemen – Complex Emergency, Fact Sheet #8, Fiscal Year (FY) 2021” September 23, 2021. Congressional Research Service 16 Yemen: Civil War and Regional Intervention of supplies. Aid groups also have increased the capacity of
intensive care units (ICUs) in COVID-19 designated hospitals from 38 in May 2020 to 59 as of intensive care units (ICUs) in COVID-19 designated hospitals from 38 in May 2020 to 59 as of
December 2020.December 2020.2973
The Public Broadcasting Service’s documentary series The Public Broadcasting Service’s documentary series Frontline has reported on how Houthi has reported on how Houthi
authorities in northern Yemen have concealed the impact of COVID-19 in areas under their authorities in northern Yemen have concealed the impact of COVID-19 in areas under their
control. According to one reporter who was permitted to visit northern Yemen in the summer of control. According to one reporter who was permitted to visit northern Yemen in the summer of
2020, Houthi authorities “put out very little public information about the spread of COVID. But 2020, Houthi authorities “put out very little public information about the spread of COVID. But
they’ve promoted propaganda videosthey’ve promoted propaganda videos ...... showing them mobilizing against the virus.”showing them mobilizing against the virus.”3074 The Houthis The Houthis
claim that the Saudi-led coalition’s blockade of Hudaydah and the Sana’a airport have claim that the Saudi-led coalition’s blockade of Hudaydah and the Sana’a airport have prevented prevented
them from procuring the supplies they need to combat the virus.them from procuring the supplies they need to combat the virus.
Human Rights Watch reports that Houthi authorities maintain a policy of withholding data on cases and deaths, and continue to block vaccination efforts and spread disinformation about the virus.75 International Pledges for Yemen
On March 1, 2021, the United Nations hosted the virtual High Level Pledging Event for the On March 1, 2021, the United Nations hosted the virtual High Level Pledging Event for the
Humanitarian Crisis in Yemen. For 2021, the U.N. is seeking $3.85 Humanitarian Crisis in Yemen. For 2021, the U.N. is seeking $3.85 billionbil ion for operations in for operations in
Yemen; however, donors pledged $1.7 Yemen; however, donors pledged $1.7 billionbil ion. Secretary Blinken spoke at the event, announcing . Secretary Blinken spoke at the event, announcing
that the United States would contribute $191 that the United States would contribute $191 millionmil ion in additional assistance, bringing total U.S. in additional assistance, bringing total U.S.
spending in FY2021 to $350 spending in FY2021 to $350 millionmil ion. The United States provided $630.4 . The United States provided $630.4 millionmil ion in total in total
humanitarian aid for the crisis in Yemen in FY2020, close to the annual average U.S. humanitarian aid for the crisis in Yemen in FY2020, close to the annual average U.S. allocational ocation
over the last four fiscal years ($644 over the last four fiscal years ($644 millionmil ion). Secretary Blinken ). Secretary Blinken calledcal ed on other donors, “especial y those in the region – to step up.”76 Other donations include $430 mil ion from Saudi Arabia, $244 mil ion from Germany, and $230 mil ion from the UAE.77 on other donors,

26 Ambassador Kelly Craft, “Remarks at a U.N. Security Council Briefing on the Situation in Yemen,” U.S. Mission to
the United Nations, February 18, 2020.
27 USAID, “Yemen – Complex Emergency, Fact Sheet #1, Fiscal Year (FY) 2021” January 22, 2021.
28 United Nations, COVID-19 Preparedness and Response Monthly Report, December 2020.
29 Op.cit., COVID-19 Preparedness and Response.
30 Public Broadcasting Service, “Yemen’s COVID Cover-Up,” Frontline, February 9, 2021.
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“especially those in the region – to step up.”31 Other donations include $430 million from Saudi
Arabia, $244 million from Germany, and $230 million from the UAE.32
Conflict Analysis
The Biden Administration has made a number of changes in U.S. Yemen policy designed to The Biden Administration has made a number of changes in U.S. Yemen policy designed to
emphasize its peacemaking role and prioritize efforts to resolve the humanitarian crisis. While the emphasize its peacemaking role and prioritize efforts to resolve the humanitarian crisis. While the
Biden Administration lifted the Trump Administration’s terrorism designations of the Houthis,Biden Administration lifted the Trump Administration’s terrorism designations of the Houthis,3378 it it
has targeted additional Houthis leaders using Yemen-specific authorities (E.O. 13611), while also has targeted additional Houthis leaders using Yemen-specific authorities (E.O. 13611), while also
condemning Houthi attacks against civilians and Saudi Arabian territory.condemning Houthi attacks against civilians and Saudi Arabian territory.3479 To date, the Biden To date, the Biden
Administration has not publicly clarified what it means by its decision to no longer support Administration has not publicly clarified what it means by its decision to no longer support
Saudi-led coalition offensive operations in Yemen, or what its defensive support to Saudi Arabia Saudi-led coalition offensive operations in Yemen, or what its defensive support to Saudi Arabia
would entail.35entails.80 According to one report, U.S. officials According to one report, U.S. officials are currently assessingassessed existing and existing and
potential sales of U.S. equipment and training to Saudi Arabia in order to determine what U.S.
support may be considered defensive.36
Despite these tangible and rhetorical steps, one could argue that developments in the war in
northern Yemen may be the most important factor in determining whether outside actors, like the
United States, are capable of bringing Yemen’s various internal factions to the negotiating table.
A rapid Houthi advance in Marib and/or the seizure its eponymous provincial capital are not a
foregone conclusion; for the ROYG government and many northern Yemenis opposed to Houthi
rule, it is a last stand. Therefore, fighting has been, and may continue to be, intense, with heavy
casualties on both sides. If the Houthis are thwarted, it would signal, at least temporarily, a
geographic limit to their rule, and perhaps an incentive for reaching a cease-fire. Such a ceasefire
would do little to resolve Houthi control over most of the rest of northern Yemen, including the
capital, Sana’a.
The extent of Saudi Arabia’s intervention using air power to support ROYG ground forces in
Marib may be pivotal, but many questions remain. How Saudi Arabia uses its air power in Marib
and elsewhere may greatly depend on understandings between it and the Biden Administration
over what constitutes a defensive or offensive air strike. Furthermore, even if Saudi preemptive
air strikes against Houthi military targets inside Yemen adhere to understandings between it and
the Biden Administration, it remains to be seen how the Biden Administration may react if Saudi
air operations kill civilians. U.S. officials have demanded a halt to the Houthi offensive in Marib,

31 U.S. potential sales of U.S. 73 United Nations, COVID-19 Preparedness and Response Monthly Report, December 2020. 74 Public Broadcasting Service, “Yemen’s COVID Cover-Up,” Frontline, February 9, 2021. 75 Human Rights Watch, “ Yemen: Houthis Risk Civilians’ Health in Covid-19,” June 1, 2021. 76 U.S. Department of State, Office of the Spokesperson, “Secretary Antony J. Blinken at the 2021 HighDepartment of State, Office of the Spokesperson, “Secretary Antony J. Blinken at the 2021 High -Level -Level
PledgingPledging Event for the Humanitarian Crisis in Yemen,” Remarks, March 1, 2021. Event for the Humanitarian Crisis in Yemen,” Remarks, March 1, 2021.
32 77 A complete list of donors is available A complete list of donors is available online at online at http://www.unocha.org/sites/unocha/files/20210103-www.unocha.org/sites/unocha/files/20210103-
YemenHLE2021_AnnouncementsResults.pdf. YemenHLE2021_AnnouncementsResults.pdf.
3378 U.S. U.S. Department of State, “Department Press Briefing, February 16, 2021,” Ned Price, Department Spokesperson, Department of State, “Department Press Briefing, February 16, 2021,” Ned Price, Department Spokesperson,
February 16, 2021. February 16, 2021.
3479 U.S. U.S. Department of State, Office of the Spokesperson, “Houthi Attacks Impacting Civilians,” Press Release,Department of State, Office of the Spokesperson, “Houthi Attacks Impacting Civilians,” Press Release, Ned Ned
Price, Department Spokesperson, February 7, 2021. Price, Department Spokesperson, February 7, 2021.
3580 In a recent State Department press conference, Spokesperson Ned Price In a recent State Department press conference, Spokesperson Ned Price remarked “Thestated, “ T he broader point is that for any broader point is that for any
weapons salesweapons sales or transfers [to Saudior transfers [to Saudi Arabia], there is now a process in place, thanks to President Biden and his efforts Arabia], there is now a process in place, thanks to President Biden and his efforts
to recalibrate this relationship from the start, that will evaluate, on a case-by-case basis,to recalibrate this relationship from the start, that will evaluate, on a case-by-case basis, proposed weaponsproposed weapons sales and sales and
transfers basedtransfers based on two criteria: our interests and our values.on two criteria: our interests and our values. And that second point, that latter And that second point, that latter point, is incredibly
important in this case.” See, U.S. Department of State, “Department Press Briefing, March 2, 2021.”
36 Patricia Zengerle and Mike Stone, “Exclusive: Biden Team Considering a Halt to 'offensive' Arms Sales for Saudis,”
Reuters, February 26, 2021.
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but the Administration has not indicated what specific military, advisory, or assistance steps, if
any, it may be willing to take to ensure that outcome.
Overall, while many in the international community wish to foster a political solution to the
Yemen conflict and thereby alleviate the dire humanitarian conditions, many internal and external
parties to the Yemen conflict do not appear presently to have clear political, military, or financial
incentives to negotiatepo int, is incredibly Congressional Research Service 17 Yemen: Civil War and Regional Intervention equipment and training to Saudi Arabia in order to determine what U.S. support may be considered defensive.81 Despite these tangible and rhetorical steps, the Houthis have made significant territorial gains in recent months and may be on the cusp of forcing the ROYG and its tribal al ies in Marib to negotiate an orderly surrender and power-sharing agreement. If the Marib front is then pacified, additional Houthi forces would be free to advance further southward into other governorates, such as Shabwa, where it could threaten Yemen’s other key energy facilities, such as the Liquefied Natural Gas Facility of Balhaf. In the view of David Schenker, a former Assistant Secretary of State for Near Eastern Affairs, “The Houthi inclination toward a military rather than a negotiated solution is paying off. Two years into their military campaign in Marib—a strategic governorate named for its capital city—the rebels are on the verge of conquering both.”82 Overal , while many in the international community wish to foster a political solution to the Yemen conflict to form a unified government with which to work to al eviate the dire humanitarian conditions, the reality on the ground resembles a fractured state, bereft of a central authority seen as legitimate by powerful actors, where internal and external parties seek to maximize control over territory and scarce resources. According to the latest U.N. Panel of . According to the latest U.N. Panel of Experts Report on Yemen, the war Experts Report on Yemen, the war
in Yemen has witnessed widespread “profiteering and control in Yemen has witnessed widespread “profiteering and control over economic resources by over economic resources by
individuals and entities.”individuals and entities.”37 83 For the Houthis, the longer they remain the de-facto authority in For the Houthis, the longer they remain the de-facto authority in
northern Yemen, the more their northern Yemen, the more their rule becomes an accepted norm, with increased potential that such rule becomes an accepted norm, with increased potential that such
legitimacy could gain more acceptance legitimacy could gain more acceptance internationallyinternational y. For the STC, the war has provided them . For the STC, the war has provided them
with a foreign patron in the with a foreign patron in the UAE UAE and a degree of local autonomy not seen since before the and a degree of local autonomy not seen since before the
unification of Yemen in 1990. For Iran, its military support to the Houthis has unification of Yemen in 1990. For Iran, its military support to the Houthis has allowedal owed it to again it to again
demonstrate how projecting power through proxy warfare is arguably a successful strategy for demonstrate how projecting power through proxy warfare is arguably a successful strategy for
expanding its regional influence. expanding its regional influence. Finally Final y, while the UAE, while the UAE may have suffered reputational damage may have suffered reputational damage
due its conduct in the Yemen war, the Emirates have gained influence along several Yemeni due its conduct in the Yemen war, the Emirates have gained influence along several Yemeni
coastal port towns and islands, such as coastal port towns and islands, such as Socotra, Mayyun, Belhaf, and Socotra, Mayyun, Belhaf, and Mukalla (see Figure 1)Mukal a. .
Leaders in Saudi Arabia, who have arguably suffered the most reputational damage over their Leaders in Saudi Arabia, who have arguably suffered the most reputational damage over their
forces’ conduct in Yemen, may feel motivated to reduce the kingdom’s military footprint in forces’ conduct in Yemen, may feel motivated to reduce the kingdom’s military footprint in
Yemen for a number of reasons including costs, stress on military forces and platforms, and the Yemen for a number of reasons including costs, stress on military forces and platforms, and the
prospect of improved relations with the United States. However, the Houthis, and more prospect of improved relations with the United States. However, the Houthis, and more
specificallyspecifical y their apparently deepening partnership with Iran, pose a key threat to Saudi security, their apparently deepening partnership with Iran, pose a key threat to Saudi security,
and military withdrawal seems likely to leave the Houthis’ militiaand military withdrawal seems likely to leave the Houthis’ militia and control over northern and control over northern
Yemen intact. If the Houthis cannot be militarilyYemen intact. If the Houthis cannot be militarily defeated, then Saudi leaders may weigh whether defeated, then Saudi leaders may weigh whether
or not the kingdom should or not the kingdom should legitimizeacquiesce to Houthi rule by Houthi rule by lifting its blockade of ending its enforcement of control over air and sea access to Yemen and negotiating Yemen and negotiating
a cease-fire. Alternativelya cease-fire. Alternatively, Saudi Arabia could seek to continue to pressure the Houthis by Saudi Arabia could seek to continue to pressure the Houthis by
sponsoring its own Yemeni proxiessponsoring its own Yemeni proxies in the hopes that one day, the balance of power will shift in its
favor. Saudi officials also may consider seeking additional U.S. engagement to combat . Saudi officials also may consider seeking additional U.S. engagement to combat
objectionable Iranian intervention in objectionable Iranian intervention in Yemen in connection with broader U.S. efforts to negotiate Yemen in connection with broader U.S. efforts to negotiate
with Iran over its nuclear program and with Iran over its nuclear program and regional policies. important in this case.” See, U.S. Department of State, Department Press Briefing, March 2, 2021. 81 Patricia Zengerle and Mike Stone, “Exclusive: Biden T eam Considering a Halt to 'offensive' Arms Sales for Saudis,” Reuters, February 26, 2021. 82 David Schenker, “Biden Needs a Plan B for Yemen if Houthis Win,” Foreign Policy, November 4, 2021. 83 United Nations Panel of Experts on Yemen, “Letter dated 22 January 2021 from the Panel of Experts on Yemen addressed to the President of the Security Council,” U.N. Document S/2021/79, January 25, 2021.regional policies.



Author Information

Jeremy M. Sharp

Specialist in Middle Eastern Affairs


37 Op.cit., Panel of Experts. .
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Yemen: Civil War and Regional Intervention

Author Information Jeremy M. Sharp Specialist in Middle Eastern Affairs

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