On Sunday the Pentagon announced that it had launched “precision defensive strikes” against an Iranian-backed militia that is believed to have been behind a recent rocket attack on a military base in Kirkuk, Iraq, that resulted in the death of a U.S. contractor.

“In response to repeated Kata'ib Hezbollah (KH) attacks on Iraqi bases that host Operation Inherent Resolve (OIR) coalition forces, U.S. forces have conducted precision defensive strikes against five KH facilities in Iraq and Syria that will degrade KH's ability to conduct future attacks against OIR coalition forces,” Jonathan Hoffman, the assistant to the Secretary of Defense, said in a statement.

The five targets included three locations in Iraq, and two in Syria. According to the Pentagon, the sites were used by Kata'ib Hezbollah to store arms and munitions, and as command and control locations from which to launch additional attacks on U.S. and partner forces.

The retaliatory strikes came days after a 30-plus rocket attack left one civilian contractor dead, and wounded four U.S. service members, and two members of the Iraqi Security Forces.

Kata'ib Hezbollah is an Iraqi militia supported by Iran, and may have ties to the country's secretive Quds Force, an arm of Iran's Islamic Revolutionary Guard Corps.

“KH has a strong linkage with Iran's Quds Force and has repeatedly received lethal aid and other support from Iran that it has used to attack OIR coalition forces,” Hoffman said in the statement. “Iran and their KH proxy forces must cease their attacks on U.S. and coalition forces, and respect Iraq's sovereignty, to prevent additional defensive actions by U.S. forces.”