Yemen: Civil War and Regional Intervention
March 12, 2021
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.
Jeremy M. Sharp
Collectively, these conflicts have eroded central governance in Yemen, and have
Specialist in Middle
fragmented the nation into various local centers of power. The gradual dissolution of
Eastern Affairs
Yemen’s territorial integrity has alarmed the United States and others in the international

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

based transnational terrorist groups; destabilize vital international shipping lanes near
the Bab al Mandab strait (also spelled Bab al Mandeb, Bab el Mendeb); and provide opportunities for Iran to
threaten Saudi Arabia’s borders.
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 the
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”)
took over the capital, Sanaa (also commonly spelled Sana’a), 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
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
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
significantly damaged the country’s infrastructure. One U.S.- and European-funded organization, the Armed
Conflict Location & Event Data Project (ACLED), estimates as of November 2020 that more than 130,000
Yemenis have been killed since 2015.
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
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
Council (STC) boiled over, leading to open warfare between the local allies of Saudi Arabia and the United Arab
Emirates. In 2020, periodic clashes continued, though both sides finally implemented a power sharing agreement
at the end of the year and formed a coalition government.
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
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
Houthis as a major factor in Yemen’s destabilization.
For several years, Yemen has been considered the worst humanitarian crisis in the world, and public health
experts warn that the Coronavirus Disease 2019 (COVID-19) pandemic may have significant negative effects on
Yemen’s vulnerable population. To date, most humanitarian agencies believe that the extent of the outbreak in
Yemen has been underreported.
For additional information on Yemen, including a summary of relevant legislation, please see CRS Report
R45046, Congress and the War in Yemen: Oversight and Legislation 2015-2020, by Jeremy M. Sharp, Christopher
M. Blanchard, and Sarah R. Collins.
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Overview ........................................................................................................................................ 1
Recent Changes in U.S. Policy ................................................................................................. 1
The Houthi-ROYG War in the North: The Battle for Marib ..................................................... 4
Clashes Continue in Hudaydah ........................................................................................... 5
Failing Oil Tanker ............................................................................................................... 5

The Houthi-Saudi Arabia Conflict ............................................................................................ 6
Southern Yemen: Tentative Unity between the ROYG and STC .............................................. 7
Iranian Support to the Houthis .................................................................................................. 8
Yemen’s Humanitarian Crisis ................................................................................................... 8

Food Insecurity & Humanitarian Access ............................................................................ 8
The COVID-19 Pandemic in Yemen ................................................................................ 10
International Pledges for Yemen ....................................................................................... 10

Conflict Analysis ...................................................................................................................... 11

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

Author Information ........................................................................................................................ 12

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Yemen: Civil War and Regional Intervention

For over a decade, the Republic of Yemen1 has been torn apart by multiple armed conflicts to
which several internal militant groups and foreign nations are parties. Collectively, these conflicts
have eroded central governance in Yemen, and have fragmented the nation into various local
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
failure may empower Yemen-based transnational terrorist groups; destabilize vital international
shipping lanes near the Bab al Mandab strait2 (also spelled Bab al Mandeb, Bab el Mendeb); and
provide opportunities for Iran to threaten Saudi Arabia’s borders. 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 the world’s
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
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 Ansar Allah, which the U.S.
government believes receives some material support from Iran. As of February 2021, the
epicenter of fighting was around the northern governorate and city of Marib (see Figure 2), one
of the last areas under the control of the internationally-recognized Republic of Yemen
Government (ROYG) led by Yemeni President Abdu Rabbu Mansour Hadi.

1 Since its 1990 unification, Yemen has been a republic in which, according to Article 4 of its 2001 constitution (as
amended), “The people of Yemen are the possessor and the source of power, which they exercise directly through
public referendums and elections, or indirectly through the legislative, executive and judicial authorities, as well as
through elected local councils.” In reality, the late President Ali Abdullah Saleh ruled a unified Yemen from 1990-
2012. 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 was endorsed by the United Nations (see, U.N. Security
Council Resolution 2014) and superseded the authority of Yemen’s constitution. As part of Yemen’s transition from
the longtime rule of President Saleh to President Hadi, all of Yemen’s various political factions (565 individual
delegates) held what was called the National Dialogue Conference (NDC) from 2013-2014. That conference was
intended to settle all of Yemen’s outstanding political issues, including producing recommendations which were to be
used by a Constitutional Drafting Committee to create a new constitution, which would then be voted on in a national
referendum. However, in January 2014 the NDC ended without agreement and shortly thereafter, the Houthis launched
a military offensive to seize large swaths of northern Yemen, culminating in their capture of the capital Sana’a in
September 2014.
2 After the Straits of Hormuz and Malacca, the Bab al Mandab is one of the world’s busiest chokepoints in terms of
volume of crude oil and petroleum liquids transported through each day. According to the Energy Information
Administration, “Total 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,
“The Bab el-Mandeb Strait is a Strategic Route for Oil and Natural Gas Shipments, August 27, 2019.
3 The Armed Conflict Location & Event Data Project (ACLED), Dashboard, available online at:
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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,
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,
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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
far less frequently than in earlier periods of the war (see Figure 4). The Yemen Data Project, a
non-profit independent data collection project, has tallied over 22,700 Saudi-led coalition air
strikes since March 2015, resulting in over 18,500 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
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
Southern Yemen: Tentative Unity between the ROYG and STC
In December 2020, the UAE-backed Southern Transitional Council (STC) formally joined a unity
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
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
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
landed at Aden airport to assume their posts, the Houthis launched a coordinated missile attack
against the airport, which killed 25 people, including three members of the International Red
While the UAE formally withdrew its main military contingent from Yemen in 2019, it has
retained a small 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
Emirates is a member of the Coalition to Restore Legitimacy in Yemen, yet its support to the
Southern Transitional Council undermines the 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 2021 from the Panel of Experts on Yemen
addressed 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
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’s Islamic Revolutionary Guard Corps-Qods Force (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
Yemen’s Humanitarian Crisis
The United Nations has described Yemen’s humanitarian crisis as currently the worst in the
world, with close to 80% of Yemen’s population of nearly 30 million needing some form of
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
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 million children under age 5 in Yemen
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 Qaddour, “Humanitarian Aid and the Biden Administration:
Lessons from Yemen and Syria,” Policy Forum Report, The Washington Institute, January 25, 2021.
24 According to senior U.N. officials, Houthi obstructions include: obstacles to beneficiary registration, attempts to
divert aid, efforts to control selection of implementing partners, detention and arrest of humanitarian workers, and
intimidation and harassment of aid workers at Sana’a airport. See Under-Secretary-General for Humanitarian Affairs
and Emergency Relief Coordinator Mark Lowcock, “Briefing to the Security Council on the Humanitarian Situation in
Yemen - As Delivered,” New York, NY, September 16, 2019. See also “UN: Houthi Rebels Impeding Aid Flow in
Yemen,” Al Jazeera English, February 19, 2020.
25 Sam Kiley, Sarah El Sirgany and Brice Lainé, “CNN exposes systematic abuse of aid in Yemen,” CNN, May 20,
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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
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 deaths; most health experts believe that these figures vastly underestimate the extent of
COVID-19 in Yemen.28 The United Nations has procured medical equipment, testing kits, and
medicine while seeking additional 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
December 2020.29
The Public Broadcasting Service’s documentary series Frontline has reported on how Houthi
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
2020, Houthi authorities “put out very little public information about the spread of COVID. But
they’ve promoted propaganda videos...showing them mobilizing against the virus.”30 The Houthis
claim that the Saudi-led coalition’s blockade of Hudaydah and the Sana’a airport have prevented
them from procuring the supplies they need to combat the virus.
International Pledges for Yemen
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 billion for operations in
Yemen; however, donors pledged $1.7 billion. Secretary Blinken spoke at the event, announcing
that the United States would contribute $191 million in additional assistance, bringing total U.S.
spending in FY2021 to $350 million. The United States provided $630.4 million in total
humanitarian aid for the crisis in Yemen in FY2020, close to the annual average U.S. allocation
over the last four fiscal years ($644 million). Secretary Blinken called 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
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,33 it
has targeted additional Houthis leaders using Yemen-specific authorities (E.O. 13611), while also
condemning Houthi attacks against civilians and Saudi Arabian territory.34 To date, the Biden
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
would entail.35 According to one report, U.S. officials are currently assessing 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. Department of State, Office of the Spokesperson, “Secretary Antony J. Blinken at the 2021 High-Level
Pledging Event for the Humanitarian Crisis in Yemen,” Remarks, March 1, 2021.
32 A complete list of donors is available online at
33 U.S. Department of State, “Department Press Briefing, February 16, 2021,” Ned Price, Department Spokesperson,
February 16, 2021.
34 U.S. Department of State, Office of the Spokesperson, “Houthi Attacks Impacting Civilians,” Press Release, Ned
Price, Department Spokesperson, February 7, 2021.
35 In a recent State Department press conference, Spokesperson Ned Price remarked “The broader point is that for any
weapons sales or transfers [to Saudi 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, proposed weapons sales and
transfers based on two criteria: our interests and our values. 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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Yemen: Civil War and Regional Intervention

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 negotiate. According to the latest U.N. Panel of Experts Report on Yemen, the war
in Yemen has witnessed widespread “profiteering and control over economic resources by
individuals and entities.”37 For the Houthis, the longer they remain the de-facto authority in
northern Yemen, the more their rule becomes an accepted norm, with increased potential that such
legitimacy could gain more acceptance internationally. For the STC, the war has provided them
with a foreign patron in the UAE 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 allowed it to again
demonstrate how projecting power through proxy warfare is arguably a successful strategy for
expanding its regional influence. Finally, while the UAE may have suffered reputational damage
due its conduct in the Yemen war, the Emirates have gained influence along several Yemeni
coastal port towns and islands, such as Socotra, Mayyun, Belhaf, and Mukalla (see Figure 1).
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
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
specifically their apparently deepening partnership with Iran, pose a key threat to Saudi security,
and military withdrawal seems likely to leave the Houthis’ militia and control over northern
Yemen intact. If the Houthis cannot be militarily defeated, then Saudi leaders may weigh whether
or not the kingdom should legitimize Houthi rule by lifting its blockade of Yemen and negotiating
a cease-fire. Alternatively Saudi Arabia could seek to continue to pressure the Houthis by
sponsoring 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
objectionable Iranian intervention in Yemen in connection with broader U.S. efforts to negotiate
with Iran over its nuclear program and regional policies.

Author Information

Jeremy M. Sharp

Specialist in Middle Eastern Affairs

37 Op.cit., Panel of Experts.
Congressional Research Service


Yemen: Civil War and Regional Intervention

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