Three American troops were killed and dozens more were injured in northeast Jordan Sunday in an attack that marked a major escalation of tensions in the region. 

The Islamic Resistance in Iraq, a loose coalition of Iran-backed militant groups, is claiming responsibility for the deadly attack. 

Per an analysis from the Pro-Israeli Washington Institute for Near East Policy, the “Islamic Resistance in Iraq,” is not a singular unit per se but rather, an umbrella term used to tie the operations of various Iran-backed proxies in Iraq and Syria. 

The report determined that an umbrella term obscures responsibility, making it more difficult to determine who is exactly responsible for attacks on U.S. targets. 

IRI said Sunday’s attack on an installation known as Tower 22 in Jordan was in retaliation for Israel’s ongoing offensive in Gaza. It regards the U.S. as complicit, given its support of Israel.

Islamic Revolutionary Guard Corps (IRGC) military personnel are walking along Enghelab (Revolution) Avenue as an Iranian Kheibar Surface-to-Surface missile is being unveiled during the Ela Beit Al-Moghaddas (Al-Aqsa Mosque) military rally in Tehran, Iran, on November 24, 2023.  (Morteza Nikoubazl/NurPhoto via Getty Images)

Since Oct. 7, militia groups have struck American military installations in Iraq and Syria – with a mix of drones, rockets, mortars and ballistic missiles – at least 160 times.

President Biden said Sunday that the U.S. “shall respond.” This after he blamed Iran-backed militia groups for the first U.S. fatalities after months of strikes by such groups against American forces across the Middle East amid the Israel-Hamas war.

The Associated Press contributed to this report.