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Houthi Attacks in the Red Sea: Issues for Congress

Updated September 6, 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 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.

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Figure 1. Maritime Incidents and Responses as of September 6, 2024

Source: CRS, using U.S. government statements and media reports. Note: Attack incidents involving multiple targets may be considered a single incident. Unreported/unacknowledged incidents not reflected. 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.

The U.S. Defense Intelligence Agency has released reports collating information about Houthi use of Iranian-origin weapons, Houthi-bound weapons seized at sea, and the effects of Houthi attacks on commercial shipping. In August 2024, the Commander of the U.S. Navy 5^th Fleet described the Houthis as having developed indigenous capacity that makes their ability to hold the region at risk “far more complex” than simple dependence on Iran. Iranian support and Houthi experience and local capacity may enable the group to pose enduring risks to security in the region beyond any resolution of the current crisis.

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Attacks in the Red Sea and Beyond

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 2023, the Houthis have attacked commercial vessels dozens of times and have posed risks to naval vessels in dozens of other incidents (Figure 1). In July 2024, a Houthi-launched drone struck Tel Aviv, Israel, prompting an Israeli response strike against the Houthi-held port of Al Hudaydah, Yemen. Maritime threats compel many firms to divert vessels from the Red Sea to the lengthier and costlier voyage around Africa, but some vessels continue to transit the area, with some suffering successful Houthi strikes.

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 organized by the Combined Maritime Forces coalition, has operated since December 2023. Bahrain, where U.S. Naval Forces Central Command (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

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humanitarian aid delivery, and preventing wider war. Congress may weigh these varied goals in considering defense and foreign operations appropriations requests for FY2025 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

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