Ten rockets have hit a base hosting US-led coalition forces in western Iraq.

Iraq's military said the rockets caused no significant losses at Al Asad air base, but security sources told AFP news agency that a civilian contractor died after suffering a heart attack.

Last month, a rocket attack in northern Iraq killed a Filipino contractor and injured a US service member.

The US blamed Iran-backed Shia militias and carried out retaliatory air strikes on one of their facilities in Syria.

President Joe Biden said the strikes - the first known use of military force by his administration - were meant as a warning to Iran and its proxies.

But Iraq's paramilitary Popular Mobilisation force, which is dominated by Shia militias, said the "sinful attack" portended "dangerous future developments".

Wednesday's rocket attack on Al Asad, where coalition troops are stationed to assist Iraqi security forces combat the Islamic State group, comes two days before Pope Francis begins a historic visit to Iraq.

The pope has insisted he will not postpone the trip despite his predecessor Benedict XVI and others warning of the risks posed by militant groups and a second wave of the country's Covid-19 epidemic.

"The people cannot be let down for a second time," the 84-year-old said in an address on Wednesday, referring to a cancelled visit by John Paul II in 2000.