An air strike by the US-led coalition battling the Islamic State group hit Iraqi security personnel yesterday, officials said, in an apparent mistake that killed eight people.

The friendly fire incident drew swift criticism of the US military presence in Iraq from pro-Iranian figures in Baghdad.

"Eight people -- a senior intelligence official, five policemen and a woman -- were killed by a US strike on the centre of Al-Baghdadi," a town in western Iraq, a provincial official said, asking not to be identified.

"It seems the strike was a mistake," the official said of the incident in the Euphrates Valley town, adjacent to the Ain al-Asad airbase 250 kilometres west of the capital.

Those killed were travelling in a convoy which had been deployed to support a dawn raid on suspected IS militants in the area.