A coalition source, speaking on condition of anonymity, said five rockets struck the Ain al-Assad base in Anbar province, according to initial reports.

"Iraqi security forces responded. No casualties or damage reported for the time being," the source added.

An Iraqi security source in Anbar had initially reported three rockets falling near the base, controlled by Iraq but hosting troops from a US-led coalition against Islamic State group jihadists.

Rockets and armed drones frequently target the Ain al-Assad base. The last such incident on April 30 saw two rockets fall nearby without causing damage or deaths.

A previously unknown group hostile to the United States' military presence in Iraq, "International Resistance", claimed responsibility for the attack on a pro-Iran Telegram channel.

Rocket and drone attacks have targeted US troops and interests in Iraq in recent months. Many are not claimed, but Washington systematically blames pro-Iran factions for them.

Iraq last year announced the end of the international coalition's combat mission after it helped the state defeat IS forces.

Some 2,500 US soldiers and around 1,000 troops from other coalition members remain in three Iraqi military bases to continue a training and advisory role that began more than a year ago.