Iran-backed groups have been launching attacks on Israeli and American targets since the outbreak of the war between its ally, the Palestinian Islamic Resistance Movement (Hamas), and Israel on October 7. This has prompted the United States to carry out counterstrikes and raised fears of broader escalation. On January 28, three American soldiers were killed in a drone attack carried out by Iran-supported militants in northeastern Jordan near the Syrian border. The U.S. accused a Tehran-backed armed group of being responsible for the attack, leading Washington to conduct airstrikes on Iranian-associated targets in Syria and Iraq. Below are the main groups involved in these attacks.
#### Islamic Resistance in Iraq
The Islamic Resistance in Iraq, which includes hardline Shiite armed groups close to Iran, claimed responsibility for an attack near the Syrian-Jordanian border around the same time U.S. officials announced that American forces were under attack. The group has claimed responsibility for more than 150 attacks on bases housing U.S. forces in Syria and Iraq since October, resulting in dozens of injuries, mostly minor, and prompting several U.S. strikes. Iranian-backed Shiite groups have emerged as key players in Iraq since the U.S.-led invasion in 2003, with their fighters numbering in the tens of thousands. These armed groups played a crucial role in the fight against the Islamic State militant group, fighting alongside popular mobilization forces. Fighters from these groups are paid by the state and are theoretically under the authority of the Prime Minister, but they often conduct operations outside the chain of command. Among the groups targeting American forces in recent months are the "Hezbollah Brigades" and the "Nujaba Movement," both closely linked to the Iranian Revolutionary Guard Corps. Their arsenal includes explosive drones, mortars, and ballistic missiles. The Islamic Resistance in Iraq stated that its operations are part of efforts to "resist U.S. occupation forces in Iraq and the region, and in response to the massacres by the Zionist entity against our people in Gaza." The U.S. classifies the Hezbollah Brigades and the Nujaba Movement as "terrorist organizations."
#### Houthis in Yemen
The Houthi group, which controls large parts of Yemen, announced its entrance into the conflict on October 31, launching drones and missiles at Israel over a thousand miles away from its base of power in Sana'a. In November, the Houthis expanded their role by attacking ships in the southern Red Sea, stating that they targeted vessels belonging to Israelis or those heading to Israeli ports, though some of the targeted ships had no known connections to Israel. These attacks prompted the United States and Britain to conduct airstrikes against Houthi targets in Yemen in January. The Houthis declared that "all U.S. and British warships involved in the aggression" against Yemen would be considered hostile targets within their sights. The attacks have disrupted international trade along the shortest shipping route between Europe and Asia, leading some shipping companies to alter their vessels' routes. The U.S. believes that the Iranian Revolutionary Guard Corps is assisting the Houthis in planning and executing missile and drone attacks. Tehran denies any involvement in these attacks. Sources told Reuters last month that "leaders from the Iranian Revolutionary Guard and the Lebanese Hezbollah group are on the ground in Yemen to help guide and oversee Houthi attacks on navigation in the Red Sea." The Houthis denied Hezbollah or Iran’s involvement in this. The U.S. has reclassified the Houthis as a terrorist group in response to the ship attacks.
#### Lebanese Hezbollah
The armed group Hezbollah has been carrying out near-daily attacks on Israeli targets along the border between Lebanon and Israel since October 8, leading to the most severe exchange of fire between the two adversaries since the large-scale war in 2006. The group claims its attacks are aimed at exhausting the Israeli military and displacing tens of thousands of Israelis from their homes near the border. Israeli airstrikes and artillery bombardments have also forced tens of thousands of Lebanese to flee. More than 150 Hezbollah fighters and at least 25 civilians in Lebanon, as well as at least nine soldiers and one civilian in Israel, have been killed. A U.S. envoy is involved in efforts to prevent the escalation of violence into a larger conflict. Hezbollah, which was established by the Iranian Revolutionary Guard in 1982, serves as a model for other Iran-backed groups throughout the region and provides advice or training to some of these groups. Hezbollah is widely regarded as more powerful than the Lebanese state and is classified as a "terrorist organization" by the United States.
