The indirect fire represents the first time US military or diplomatic installations have been targeted in Iraq in nearly two months.

At around 9:30 pm (1830 GMT), an AFP reporter heard several loud explosions in the northwestern outskirts of Arbil, the capital of Iraq's autonomous Kurdistan region.

Iraqi and Western security sources told AFP that at least three rockets were fired in the direction of the airport.

Two hit residential neighbourhoods on Arbil's outskirts.

There was no immediate information on casualties.

Western military and diplomatic sites have been targeted by dozens of rockets and roadside bomb attacks since the autumn of 2019, but most of the violence has taken place in Baghdad.

Both American and Iraqi officials have blamed hardline armed groups, including the pro-Iran faction Kataeb Hezbollah and Asaib Ahl al-Haq.

These groups are vehemently opposed to the US-led coalition, which has been based in Iraq since 2014 to help local forces fight back the Islamic State group.

With IS largely defeated, the coalition has drawn down to under 3,500 forces in total, 2,500 of which are US troops.

Most of those units are concentrated at the military complex at the Arbil airport, a coalition source told AFP.

But most rocket attacks had concentrated on the coalition and US diplomatic personnel based in Baghdad.

In October, the US threatened to close its embassy there if the rocket attacks did not stop, so hardline groups agreed to an indefinite truce.

There have been several violations since then, the most recent of which, prior to Monday night, was a volley of rockets targeting the US embassy on December 20.