At least a dozen missiles were fired on Saturday at a military base used by US-led coalition forces in western Iraq, a US defence source and Iraqi police told AFP.

"Al-Asad airbase was targeted by 15 rockets" fired from Anbar province, which is home to the military base, an Iraqi police official from the region told AFP, speaking on condition of anonymity.

He said 13 of the projectiles were shot down by anti-air defences but that "two fell on the airbase".

A US defence official, who also requested anonymity, confirmed that "missiles impacted Al-Asad airbase", adding that a joint damage assessment was under way with coalition and Iraqi forces.

The American official said that initial reports indicated one member of the Iraqi security forces had been seriously injured.

In a press release, the Islamic Resistance in Iraq, a loose alliance of Iran-linked armed groups that oppose US support for Israel in the Gaza conflict, said it carried out the attack.

Saturday's air base attack comes amid soaring tensions in the Middle East following the outbreak of the Israel-Hamas war on October 7.

On Saturday, five members of Iran's Islamic Revolutionary Guard Corps were killed in a strike in Damascus that Tehran blamed on Israel, threatening reprisals. 

On Monday evening, Iran itself launched a deadly strike in northern Iraq's autonomous Kurdistan region, saying it had targeted a site used by "spies of the Zionist regime (Mossad)".

Since mid-October, there have been dozens of attacks on US and coalition forces in Iraq and Syria, deployed there to fight jihadists of the Islamic State group.

Most have been claimed by "Islamic Resistance in Iraq".

Washington has on several occasions launched strikes of its own in retaliation.

There are roughly 2,500 American troops in Iraq and some 900 in Syria.