October 18, 2023 | Flash Brief

Iran-Backed Militias Attack U.S. Forces in Iraq

October 18, 2023 | Flash Brief

Iran-Backed Militias Attack U.S. Forces in Iraq

Latest Developments

Shiite militias backed by Tehran targeted two U.S. bases in Iraq on October 18 with Iranian-made suicide drones. The militias claimed the attacks were a response to Washington’s support of Israel in its war against Hamas. The U.S. military said it thwarted two armed drones before they could strike the al-Asad air base in western Iraq. Later that day, U.S. forces thwarted another armed drone that targeted al-Harir air base located in the semi-autonomous Kurdish province of Erbil in northern Iraq. U.S. Central Command reported that a member of the coalition forces received minor injuries from the drone attack on al-Asad but reported no injuries from the al-Harir attack.

Expert Analysis

“The Iran-backed militias are a dangerous force multiplier for Iran and the ‘Islamic Resistance.’ With hundreds of thousands of battle-hardened fighters at their disposal, these militias can serve as a strategic reserve in a war with Israel and pose a direct threat to U.S. interests throughout the Middle East.” Bill Roggio, Senior Fellow and Editor of FDD’s Long War Journal

“The success of Hamas and other Palestinian terrorist groups in the October 7 attack has emboldened Iran and its terrorist proxies in the region. In targeting U.S. troops, Tehran aims to convey a resolute message to the United States to steer clear of any involvement in the Gaza conflict. Otherwise, American forces may face the threat of additional attacks orchestrated by Iranian proxies in the region.” Joe Truzman, Research Analyst at FDD’s Long War Journal

“If the United States responds weakly to attacks on its forces, Washington will only invite more attacks.” Bradley Bowman, Senior Director of FDD’s Center on Military and Political Power

Islamic Resistance Claims Reponsibility

A group calling itself the “Islamic Resistance in Iraq” — a network of shadow Iraqi militia groups affiliated with the Islamic Revolutionary Guard Corps (IRGC) — claimed the attack on al-Asad. Another little-known Shiite militia, Tashkil al-Waritheen, took responsibility for the attack on al-Harir.

“Islamic Resistance” is a euphemism used by Iranian-backed groups to refer to each other, including groups outside of Iraq such as Hezbollah, Islamic Jihad, and Hamas. Over the past several years, Iran-backed Shiite terror groups have launched sporadic attacks against U.S. bases in Iraq and Syria. Since the war in Gaza began on October 7, several Shiite militias have issued direct threats to U.S. interests in Iraq and across the Middle East.

Shiite Militias Issue Statements Threatening U.S. and Israel

The Badr Organization, the Hezbollah Brigades, and Kata’ib Sayyid al-Shuhada are the most powerful and influential Iran-backed Shiite militias comprising Iraq’s Popular Mobilization Units (PMU). On October 17, Iraq-based Hezbollah Brigades blamed the fighting in Gaza on “American-backed criminal Zionism” and warned that “these evil people [Americans] must leave the country. Otherwise, they will taste the fire of hell in this world before the afterlife.” Other PMUs have not yet issued statements, including the Asaib Ahl al-Haq, Saraya Khorasani, Harakat al-Nujaba, and Kata’ib Imam Ali.

Militias Have Killed U.S. Troops

PMUs are established, armed, and trained by the IRGC and have killed more than 600 American troops since 2003. While their loyalty lies with Iran, which wishes to see U.S. forces leave the Middle East, PMUs have been recruited by the Iraqi government to fight the Islamic State and have also helped fight anti-Assad forces in Syria. Akram al Kaabi, leader of Harakat al-Nujaba, has sworn to follow the orders of Iran’s supreme leader.

U.S. Surges Additional Combat Forces to the Middle East,” FDD Flash Brief

State designates Iran-backed League of the Righteous as Foreign Terrorist Organization,” by Bill Roggio

Iran’s Escalating Threats: Assessing U.S. Policy Toward Iran’s Malign Activities,” by Behnam Ben Taleblu

Another Iraqi Shia militia threatens the United States over involvement in Israel,” by Joe Truzman


Iran Iran Global Threat Network Iran-backed Terrorism Kurds