The United States launched airstrikes on several military bases of the Popular Mobilization Units (PMU) in southern Iraq early Friday. The strikes mark an escalation in tensions between the United States and Iran on Iraqi territory, putting Iraq at risk of becoming a site of war between the countries' proxies.

The US attack was retaliation for an attack on Camp Taji base in northern Baghdad March 11, which killed two American and one British soldier. Kataib Hezbollah and Nujaba Movement, though they did not take credit for the attack, praised it and expressed support for the perpetrators.

The United States had warned that it would take all necessary measures to prevent attacks on its forces in Iraq. “We will take any action necessary to protect our forces in Iraq and the region,” US Defense Secretary Mark Esper said.

Iraqi Joint Operations Command issued a statement immediately after the US attack March 13, stating that the United States had attacked the 19th Division of the Iraqi army, the headquarters of a unit of the Popular Mobilization Units, and the 3rd Babylon Police Regiment. The areas attacked include Jurf al-Nasr, al-Saeedat and Behbehani.