Iran-backed Iraqi paramilitary groups launched a rocket attack targeting U.S. troops in the semiautonomous Kurdistan Region's capital, Irbil, Iraqi Kurdistan's counterterrorism service said on September 30.

"Six rockets were launched from the borders of the Sheikh Amir village in Nineveh province by the Popular Mobilization Forces who were targeting (U.S.-led) coalition forces in Irbil International Airport," the service said in a statement.

Four rockets landed at the edge of the airport compound and two did not explode, it added.

The attack "is yet another escalation to disrupt security in #Iraq and #IraqiKurdistan," Hoshyar Zebari, a former Iraqi foreign minister and a politician in Kurdistan, said on Twitter.

Based on reporting by Reuters and AFP