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INSIGHTi
Houthi Attacks in the Red Sea:
Issues for Congress
Updated January 31, 2024
Since the October 7, 2023, Hamas attacks and Israel’s military response in Gaza, the Ansar Allah/Houthi
movement, an Iran-backed force in Yemen, has targeted (Figure 1) Israeli territory and commercial and
naval vessels near the Bab al Mandeb Strait, a key maritime choke point. In response, the United States,
its allies, and partners have intercepted Houthi-launched projectiles, formed a coalition to patrol the Red
Sea, demanded the Houthis halt attacks, designated the Houthis and Houthi defense figures for sanctions,
and struck Houthi targets in Yemen. Nevertheless, attacks have persisted, diverting maritime traffic from
the Red Sea and driving up shipping costs. On January 10, the United Nations Security Council adopted
Resolution 2722, condemning Houthi attacks and noting member states’ rights to defend their vessels.
On January 11, 2024, the United States, the United Kingdom, and others conducted joint strikes on 60
Houthi targets across 16 different locations in Yemen. Prior to these strikes, some lawmakers had
criticized the Biden Administration’s response and called for greater pressure on the Houthis. President
Joe Biden entered office in 2021 vowing to pursue de-escalation of Yemen’s long-running civil war. U.S.
and allied strikes have continued, as officials reiterate their goals of avoiding regional war and express
concern that Houthi attacks and international responses may undermine progress made toward peace in
Yemen.
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CRS INSIGHT
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Figure 1. Maritime Incidents and Responses as of January 28, 2024
Source: CRS, using U.S. government statements and media reports.
Note: Attack incidents involving multiple targets may be considered a single incident. Data subject to revision.
The Houthis: Background, Conflict, and Iranian Support
The Houthi movement (formally known as Ansar Allah or Partisans of God) is a predominantly Zaydi Shia revivalist political
and insurgent movement formed by the Houthi family in northern Yemen in 2004. The group espouses anti-American and
anti-Zionist beliefs. From 2004 to 2014, it consolidated local power, at times warring with Saudi Arabia to its north and the
former Yemeni central government to its south. In 2014, after the Houthis rejected the results of a national dialogue, the
group resumed its insurgent posture, seized the capital, Sana’a, and later advanced on Aden. Yemen’s then-leaders fled and
requested international intervention. In March 2015, a coalition led by Saudi Arabia began a counter-Houthi military
campaign. Houthi cross-border attacks grew in complexity and scope over time with deepening support from Iran. An
uneasy truce has frozen conflict lines since 2022.
Iran has provided the Houthis with components and technical knowledge to construct long-range missiles and rockets and
unmanned aerial vehicles (UAVs). Houthi fighters have trained at an Iranian naval academy and received instruction from
Iran’s Islamic Revolutionary Guard Corps (IRGC). The Houthis now wield anti-ship ballistic missiles and UAVs with ranges
up to 1,000 miles. In January, Iran deployed an aging frigate in the Red Sea ostensibly to escort Iranian ships, but some
observers suspect it provides the Houthis with assistance in planning attacks and with “tactical intelligence.”
Attacks in the Red Sea
In October 2023, the Houthis threatened to intervene on behalf of the Palestinians against Israel, and in
November the Houthis announced that they would attack Israeli ships in the Red Sea and downed a U.S.
drone. In December, the Houthis expanded potential targets to include all ships sailing to Israeli ports if
humanitarian aid delivery to Gaza was not expanded. In January, the group responded to U.S.-led strikes
in Yemen by threatening U.S.- and U.K.-owned vessels. Many Houthi attacks on commercial vessels have
not appeared discriminate or linked to stated demands. Since October 17, the Houthis have attacked
commercial and naval vessels more than 30 times (Figure 1). The threats compel many firms to divert
vessels from the Red Sea to the lengthier and costlier voyage around Africa.
U.S. Response
Prior to the start of U.S.-led coalition strikes in Yemen, U.S. naval forces responded militarily to Houthi
provocations by intercepting Houthi missiles and UAVs and interdicting attempted Houthi vessel seizures.
Interception incidents continued throughout January. Operation Prosperity Guardian, a 22-nation coalition
led by U.S. Naval Forces Central Command (NAVCENT), has operated since December 2023. Bahrain,
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where NAVCENT is headquartered, is the only Arab member of the coalition. Two U.S. servicemembers
died in a January operation that seized Iranian-origin missile components and weapons on a Yemen-bound
ship. In January 2024, the Biden Administration announced that the Houthis would be redesignated as
Specially Designated Global Terrorists (SDGT), effective February 16, and sanctioned Houthi officials.
Diplomatic joint statements have endorsed U.S. and U.K. military strikes against the Houthis and
demanded an end to what they described as the Houthis’ “illegal and unjustifiable attacks.” Canada,
Australia, Bahrain, and the Netherlands have provided “nonoperational support” for strikes. U.S. officials
have asserted that U.S. action is “grounded in Article 51 of the United Nations Charter” and “reflects our
inherent right to self-defense.” The President informed Congress that he ordered the January 11 strikes
“pursuant to my constitutional authority as Commander in Chief and Chief Executive and to conduct
United States foreign relations.”
Issues for Congress
U.S.-led strikes have received some bipartisan approval, though some lawmakers call them long overdue
or call for more, while others call them “unauthorized” or question the Administration’s legal views on
the matter. Some lawmakers call for a redesignation of the Houthis as a Foreign Terrorist Organization
(FTO), a status with legally defined designation and revocation criteria. Risks include a widening conflict
involving the United States or the potential for resumption of Yemen’s civil war. U.S. goals in Yemen
include consolidating U.N.-backed peace efforts, restoring maritime security, interdicting Iranian
weapons, combatting transnational terrorists, ensuring humanitarian aid delivery, and preventing wider
war. Congress may weigh these varied goals in considering possible requests for supplemental funding
and issues related to authorization for the use of force.
Abigail Martin, CRS Research Assistant in the Foreign Affairs, Defense and Trade Division, and Jeremy
Sharp, Specialist in Middle Eastern Affairs, contributed to this Insight.
Author Information
Christopher M. Blanchard
Specialist in Middle Eastern Affairs
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff
to congressional committees and Members of Congress. It operates solely at the behest of and under the direction of
Congress. Information in a CRS Report should not be relied upon for purposes other than public understanding of
information that has been provided by CRS to Members of Congress in connection with CRS’s institutional role.
CRS Reports, as a work of the United States Government, are not subject to copyright protection in the United
States. Any CRS Report may be reproduced and distributed in its entirety without permission from CRS. However,
as a CRS Report may include copyrighted images or material from a third party, you may need to obtain the
permission of the copyright holder if you wish to copy or otherwise use copyrighted material.
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