The U.S. on Wednesday morning delivered its most aggressive response to date against constant attacks from Iran-backed militia groups, conducting airstrikes against two facilities controlled by one of the most powerful militias, Kata’ib Hezbollah (KH).

The Iraqi government, which has done little to curb the attacks despite numerous requests from the Biden administration, condemned the U.S. strikes as “dangerous escalation.”

U.S. Central Command (CENTCOM) said it conducted “discrete, precision strikes” against the facilities “in direct response to the attacks against U.S. and Coalition forces by Iran and Iran-backed groups, including the one in Iraq on November 21, which involved use of close-range ballistic missiles.”

The November 21 attack CENTCOM referred to involved a close-range ballistic missile launched by Iranian proxy forces against Al-Asad Airbase in Iraq. The missile detonation caused “eight injuries and minor structural damage,” according to the Pentagon.

The ballistic missile strike was a significant escalation from earlier militia attacks in Iraq and Syria, which generally used less powerful rockets and bomb-laden drones. The Pentagon counted 66 attacks against U.S. forces since October 17, 32 in Iraq and 34 in Syria, with 62 injuries to U.S. personnel before the ballistic missile attack.

“Immediately following the attack, a U.S. military AC-130 aircraft in the area conducted a self-defense strike against an Iranian-backed militia vehicle and a number of Iranian-backed militia personnel involved in this attack,” Pentagon spokesman Brig. Gen. Pat Ryder said.

The Lockheed AC-130 is a venerable fixed-wing gunship whose design dates back to the Vietnam War. Modern AC-130 platforms are more sophisticated and heavily armed than their ancestors, but their basic operational principle remains the same: a large aircraft with an assortment of powerful weapons mounted on one side, pouring fire into the targets as the plane flies in a circle around them.

CENTCOM said the AC-130 “maintained visual confirmation of the individuals from the time of the launch to the time of engagement,” which would suggest the Iraqi militia fighters did not enjoy the rest of their evening after launching their ballistic missiles.

The two strikes on KH targets announced by CENTCOM on Wednesday morning were in addition to the immediate gunship response to the Al-Asad Airbase attack. U.S. defense officials said the strikes, conducted by fighter aircraft, destroyed a KH “operations center” and “command and control node” south of Baghdad.

Unlike the Biden administration’s previous retaliatory strikes for militia attacks, both of the KH facilities were reportedly manned at the time of the U.S. airstrikes. CENTCOM was still assessing casualties from the airstrikes on Wednesday morning, while KH claimed eight of its members were killed. 

The Iraqi government condemned the U.S. strikes as “a clear violation of sovereignty and an attempt to disrupt the stable internal security situation.”

The Iraqi statement said U.S. and international forces were supposed to be present in an “advisory role” to fight the Islamic State, which is also the nominal purpose of the Iran-backed militia groups. Iraq deputized those militias as “Popular Mobilization Forces” (PMF) after ISIS invaded from Syria. This had the unfortunate side effect of greatly increasing Iran’s influence over Iraqi politics.

The growing influence of the PMF has been especially troubling to the Kurds, who have their own semi-autonomous region in northern Iraq. Kurdish officials were outraged when Shiite militia groups targeted airbases in the Kurdistan Region with drone attacks in November. Kurdish president Nechirvan Barzani called on Iraqi Prime Minister Mohammed Shia al-Sudani to “prevent outlaw forces from creating issues for Iraq and the Kurdistan Region.”

Iraq complained the U.S. strikes were conducted “without the knowledge of Iraqi government agencies,” which made them an “unacceptable violation of Iraqi sovereignty.” 

The Iraqi government also criticized the Iran-linked Shiite militia groups for committing dozens of attacks on U.S. forces since the Israel-Hamas war began in October, noting that “any armed action or activity outside the military institution is deemed condemnable and an unlawful endeavor that jeopardizes the national interest.”

Kata’ib Hezbollah issued a statement saying the U.S. airstrikes “will not go unpunished.”