Iran-Supported Groups in the Middle East and U.S. Policy

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Updated September 26, 2024

Iran-Supported Groups in the Middle East and U.S. Policy

Iran has long backed a network of armed groups in the Middle East to advance its regional interests. These groups, which include U.S.-designated Foreign Terrorist Organizations (FTOs) and which sometimes style themselves the “Axis of Resistance,” have conducted attacks on U.S., Israeli, and other targets for years. The number, pace, and scope of such attacks have surged since the October 7, 2023, Hamas-led assault on Israel from Gaza. Arenas of ongoing conflict include the war between Hamas and Israel in Gaza; attacks by the Houthis in Yemen against international shipping and U.S. military vessels in the Red Sea; Iraqi group attacks against Israel; and escalating strikes between Lebanese Hezbollah and Israel. U.S. policymakers may evaluate various means of deterring and responding to such attacks (such as diplomacy or military strikes, whether on militia groups, Iranian personnel abroad, or inside Iran), and the potential benefits, costs, and unintended consequences of these options.

Iran’s Foreign Policy

Support for regional nonstate actors has been a pillar of the Iranian government’s foreign policy since the 1979 founding of the Islamic Republic. Iran supports these groups to advance its foreign policy aims, including to position itself as the defender of Shia Muslim communities and other groups that the Iranian government characterizes as oppressed, such as the Palestinians. Perhaps preeminent among these aims is reducing threats that Iran may face stemming from the regional influence of the United States and its regional allies, with which the Iranian government “sees itself as locked in an existential struggle,” according to a public assessment by the U.S. intelligence community. Support for these groups carries strategic benefits and risks for Iran. Iranian leaders might see supporting armed groups as a cost-effective way to project power, given that Iran lacks some key conventional military capabilities. The sometimes-opaque nature of Iranian assistance for these groups suggests Iran may seek to avoid responsibility for its beneficiaries’ actions. At the same time, the United States and others may still hold Iran accountable, including for actions that Iran may not have specifically directed or approved in advance. The increasingly open nature of direct Israel-Iran clashes may indicate that sponsorship of actors abroad may provide less deterrence than Iran has possibly sought as part of what some Iran experts have called a “forward defense” strategy. The Qods Force (QF) of Iran’s Islamic Revolutionary Guards Corps (IRGC) coordinates Iranian support to armed groups abroad; both the IRGC and IRGC-QF are designated for U.S. sanctions under terrorism-related authorities.

Selected Iran-Backed Groups

According to U.S. officials, the groups profiled below are prominent beneficiaries of Iranian government support. The

nature and degree of Iranian support vary: while all share some key interests with Tehran, to differing extents they also may act independently in pursuit of their own interests.

Lebanese Hezbollah

Arguably the most powerful Iranian-backed group and a key player in Lebanese politics, Hezbollah (“Party of God,” alt. Hizballah) most closely represents an Iranian proxy; it often aligns directly with, and acts on behalf of, Tehran. Founded in the context of the Lebanese civil war and Israeli invasion, Hezbollah was established in 1982 by Lebanese Shia militants who were inspired by, and received critical assistance from, the new Islamic Republic of Iran. Per the State Department, Iran “continues to provide Hizballah with most of its funding, training, weapons, and explosives, as well as political, diplomatic, monetary, and organizational aid.” Hezbollah attacked U.S. targets in Lebanon during the country’s civil war, and has since targeted Israeli and Jewish targets in several countries. Hezbollah has reportedly provided support to many of the groups below.

Hezbollah (which fought an inconclusive 34-day war with Israel in 2006) has launched projectiles into Israel since October 2023 in stated solidarity with Hamas; Israel has responded with airstrikes in Lebanon, and both sides have taken steps to escalate since July 2024. The conflict has reportedly displaced tens of thousands in Israel and hundreds of thousands in Lebanon. Israeli officials have threatened wider military action seeking to enable the return of evacuated Israelis; Hezbollah has insisted that Israel first halt fighting in Gaza. In September to date, Israeli operations against Hezbollah have killed hundreds in Lebanon. Analysts debate the extent to which those operations have affected Hezbollah’s strategic calculus, military capabilities (including its arsenal of some 150,000 missiles and rockets), and internal cohesion.

Hamas

Iran has aided the Sunni Islamist Palestinian group Hamas for decades, going back nearly to the group’s inception in the late 1980s. Since Hamas took de facto control of the Gaza Strip in 2007, it has engaged in several rounds of conflict with Israel, with material and financial support from Iran. The State Department assesses that Iran provides “up to $100 million annually in combined support to Palestinian terrorist groups, including Hamas.” Hamas has reportedly received additional material support from private entities in other regional countries, and also has secured resources via its governance of Gaza.

The Office of the Director of National Intelligence assessed in February 2024 that “Iranian leaders did not orchestrate nor had foreknowledge of” the October 7 attack. The Biden Administration has contended that Iran is “broadly complicit in these attacks,” as Hamas’s “primary backer for decades.” Top Hamas political leader Ismail Haniyeh

Iran-Supported Groups in the Middle East and U.S. Policy

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reportedly was killed in July 2024 in Tehran, where he and senior representatives from other Iran-backed armed groups had gathered for the inauguration of Iran’s new president; Iran has blamed Israel and vowed to retaliate.

The Houthis

The Iranian government has long backed the Yemeni Shia militant group Ansar Allah, aka the Houthis, and has increased its support since the group took control of Yemen’s capital and much of the north in 2014-2015. Iran’s support to the Houthis—including ballistic and cruise missiles and unmanned weapons systems—has reportedly enabled the group to attack the territories of U.S. partners, including Saudi Arabia and the United Arab Emirates.

The Houthis have espoused categorically anti-Israel views for decades, and since October 2023 have claimed several missile attacks against Israel; many have been intercepted by Israeli or U.S. forces, but a July 2024 missile attack on Tel Aviv killed one Israeli, prompting Israeli retaliatory airstrikes in Yemen. The Houthis assert that they are demonstrating solidarity with the Palestinians with these strikes, and also by conducting attacks on commercial and naval vessels in the Red Sea since November 2023 that have impacted global trade. The United States and partner nations have deployed military assets to the region to respond to the Houthi attacks, thwarting Houthi hijackings of commercial vessels and exchanging fire with Houthi forces since January 2024.

Iraqi Militias

Iran has deeply rooted ties in neighboring Iraq, where it works with a number of powerful military and political groups, mostly from Iraq’s Shia majority. These groups gained combat experience and deepened their ties with Iran during operations against the Islamic State (IS) starting in 2014, and have leveraged that experience to become prominent actors in Iraq’s political system. Since 2017, Iran-backed Iraqi groups have conducted attacks against U.S. forces in Iraq and Syria, to which the United States has periodically responded with airstrikes. U.S.-designated

FTOs in Iraq linked to such attacks include Kata’ib Hezbollah (KH), Harakat al Nujaba (HN), and Asa’ib Ahl al Haq (AAH). Attacks by those groups on U.S. forces in Iraq and Syria multiplied after October 2023, prompting U.S. strikes. The Iraqi government in turn seeks to end the U.S.-led counter-IS coalition mission in the country. A January 2024 attack claimed by Iran-backed Iraqi militants killed three U.S. servicemembers in Jordan, triggering U.S. retaliatory airstrikes. Attacks and U.S. responses subsided for several months before resuming in July 2024. Iraqi groups have claimed long range strikes targeting Israel.

U.S. Policy

The Biden Administration has sought to deter and respond to attacks from Iran-backed groups, and has committed to helping Israel defend itself, while seeking to avoid a deeper regional conflict. It has attempted to help the parties negotiate cease-fires in Gaza and Lebanon. Iranian officials have stated support for attacks and said they will continue until the war in Gaza ends, while denying that they control the groups carrying out those attacks. Iran’s new president has blamed Israel for seeking to “create this all-out conflict.” U.S. and Iranian officials have stated that messages have been relayed regarding an intention to avoid wider war.

Some Members of Congress have supported the Administration’s actions to date. Others have called for direct U.S. strikes on Iran, claiming that operations elsewhere do not deter Iran or the groups it supports. Others assert that the Administration lacks congressional authorization for U.S. forces to target Iran-backed groups.

The U.S. military has struck Iranian assets and personnel abroad (e.g., the 2020 strike that killed then-IRGC-QF commander Qasem Soleimani) but has not claimed any strikes within Iran. A broader military conflict with Iran could entail major costs for the United States, and may cause Iran to accelerate its nuclear activities or target U.S. forces and/or partners.

Figure 1. Selected Iran-Supported Groups

Source: Created by CRS, based on U.S. Department of State, Country Reports on Terrorism, and other public sources.

Clayton Thomas, Specialist in Middle Eastern Affairs

Iran-Supported Groups in the Middle East and U.S. Policy

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