Three Katyusha rockets slammed into the joint U.S./Iraqi base at Taji on Monday night. No casualties were reported, although one Iraqi helicopter was damaged. It was the second rocket attack in the past three days against U.S-led coalition bases. On Friday, Katyusha rockets had hit the Besmaya base and caused material damage, but again, no casualties were reported.

Iraq’s military took to Twitter to announce that the rockets which hit al-Taji base were launched from Saba’ al-Bour, an area to the base’s southeast. Despite being aimed at the U.S-led coalition troops, the rockets fell on an area of the base used by Iraqi forces.

“Initial information indicates that the missile attack left only physical damages,” Iraqi military spokesman Captain Ahmed Khalaf said to the media. The base was targeted by four Katyusha rockets, according to Khalaf.

Three of the four missiles hit the base. One of them “caused significant damage to the aircraft of the Iraqi army,” the other caused material damage to the factory for the production of artillery guns, the third did not explode.

The al-Taji airbase is located about 53 miles north of the Iraqi capital of Baghdad. 

While no one has claimed responsibility for the rocket attack, there can be little doubt that this was just another attack by the Iranian-led militias that are part of the Popular Mobilization Forces (PMF). Kata’ib Hezbollah, which has been behind many of the more than three dozen attacks against the U.S.-led coalition in the past several years, is a prime suspect.

Iraqi Prime Minister Mustafa al-Kadhimi, under pressure from Washington, has vowed to crack down on the PMF units that have continued to attack American bases. Last month he ordered his security services to raid a Kata’ib Hezbollah headquarters after the U.S. and Iraqis learned of an upcoming rocket attack on a U.S. base. 

The raid led to the arrest of 14 members of the militia as well as the capture of three rocket launchers The leader of the militia has warned the Prime Minister not to interfere with the militia’s actions. While they are, in theory, supposed to be taking their orders from the Baghdad, the militias, raised and ran by the Quds Force of the Iranian Revolutionary Guard Corps, take their orders from Iran. 

After attacks that killed American and coalition service members in December, the U.S. launched airstrikes against several PMF locations. Under orders from Major General Qassem Soleimani, the militias attacked U.S. areas in the Green Zone of Baghdad. They also attempted to storm the U.S. Embassy. 

That led to a drone airstrike just outside of the Baghdad airport that targeted and killed Soleimani and the commander of the Iranian proxy Kata’ib Hezbollah militia, Abu Mahdi al-Muhandis — a designated terrorist in the U.S.

The Iraqi government, which had virtually ignored all of the attacks on the U.S-led coalition, said the drone strike that killed Soleimani undermined its national sovereignty. It considered it a breach of its bilateral security agreements with the U.S. and an act of aggression against its officials. On January 5, the Iraqi parliament passed a non-binding resolution to expel all foreign troops from its territory. The Iranians interpreted the resolution to concern just the U.S.-led coalition. 

Five days later, Iran launched a ballistic missile attack against other U.S. bases in Iraq. Later that same evening, nervous Iranian air defense missile operators fired on, and shot down Ukraine International Airlines Flight 752, killing all 176 people on board. 

This latest series of incidents could be an attempt by Iran to goad the United States into retaliating and then using that in an attempt to undermine the administration of Prime Minister al-Kadhimi.