A group of suicide bombers from the Islamic State group killed three Iraqi soldiers Saturday in an attack on a military base hosting hundreds of coalition advisers, officers said.

"Four suicide bombers this morning infiltrated the military base of Al-Asad on its northern edge," said Major General Ali Ibrahim Daboun, head of the Al-Jazeera Operations Command.

"The bombers were of various nationalities, they were killed by Iraqi security forces," he told AFP, without specifying any casualties among army ranks.

Al-Asad air base, located about 180 kilometres (110 miles) northwest of Baghdad in Anbar province, is one of the largest military installations in the country.

It is home to Iraqi federal forces and tribal fighters currently engaged in operations to retake the nearby town of Hit from IS, as well as to a large contingent of foreign military advisers.

Colonel Steve Warren, the spokesman for the US-led coalition fighting IS in Iraq and Syria, said no foreigners were involved in the incident.

Another Iraqi security source said the number of bombers was higher than four and said one of them managed to detonate his suicide vest, killing three Iraqi soldiers and wounding four.

"One of the killed soldiers had the rank of major," the officer said on condition of anonymity because he is not authorised to speak to the press.

The Baghdad-based "war media cell" that issues statements for Iraq's myriad pro-government forces also said three soldiers had been killed in the attack.

It said the site of the IS attack was an outpost on the northern edge of Al-Asad base and warned that the casualty figures were provisional.

Jihadist fighters are holed up in Hit, a Euphrates Valley town about 145 kilometres west of Baghdad, with Iraqi forces closing in on them from several sides.

The government has had to pull several units out of the Anbar offensive however to beef up security in Baghdad, where protesters have been camping outside the fortified Green Zone to demand reforms.