link to page 2 
INSIGHTi
Houthi Attacks in the Red Sea:
Issues for Congress
Updated May 1, 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.
The United States and the United Kingdom, with support from other countries, conducted joint strikes on
Houthi targets across different locations in Yemen on January 11, January 22, February 3, and February
24. 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 undermine progress made
toward peace in Yemen.
Congressional Research Service
https://crsreports.congress.gov
IN12301
CRS INSIGHT
Prepared for Members and
Committees of Congress
Congressional Research Service
2
Figure 1. Maritime Incidents and Responses as of May 1, 2024
Source: CRS, using U.S. government statements and media reports.
Note: Attack incidents involving multiple targets may be considered a single incident. Data approximate and 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.
Houthi military capabilities include ballistic missiles, cruise missiles, rockets, and unmanned aerial and underwater/surface
vehicles, in addition to conventional and unconventional air and ground forces. Iran provides a range of material and
advisory support to the Houthis, according to U.S. officials. U.S. Central Command Deputy Commander Vice Admiral Brad
Cooper said in February 2024 that
For a decade, the Iranians have been supplying the Houthis. They`ve been resupplying them. They`re resupplying
them as we sit here right now, you know, at sea. We know this is happening. They`re advising them. And
they`re providing targeting information. This is crystal clear. .. The Iranian Revolutionary Guard Corps is inside
Yemen. And they are serving side by side with the Houthis, advising them and providing targeting information.
link to page 2 Congressional Research Service
3
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 vessels at least 53 times and have posed risks to naval vessels in dozens of other incidents
(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 24-nation coalition
led by U.S. Naval Forces Central Command (NAVCENT), has operated since December 2023. Bahrain,
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, January
22, February 3, and February 24 strikes “pursuant to my constitutional authority as Commander in Chief
and Chief Executive and to conduct United States foreign relations.” Other U.S. Central Command
statements have described U.S. strikes targeting sites and equipment “prepared to launch” as “self-defense
strikes.” U.S. forces destroyed Houthi weapons prepared to launch amid Iran’s April 2024 missile and
drone attack on Israel.
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. The Fiscal Year (FY) 2024
national security supplemental act (P.L. 118-50) made available $2.4 billion for operations, force
protection, deterrence, and the replacement of combat expenditures in the U.S. Central Command area of
operations. In April, the House adopted H.R. 6046, which would direct the Secretary of State to designate
the Houthis as an FTO not later than 90 days after enactment.
Risks of the current crisis 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 defense and foreign operations appropriations requests for Fiscal Year 2025 and issues related
to authorization for the use of force.
Congressional Research Service
4
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.
IN12301 · VERSION 6 · UPDATED