A bomb blast initially targeted a truck transporting the men. It was followed by "a direct attack with small arms", near the village of Chalal al-Matar, a federal police officer who attributed the assault to IS, told AFP on condition of anonymity.

No group immediately claimed responsibility for the attack.

"An assailant has been killed and we are looking for the others," the officer said, adding that two policemen were also wounded in the attack.

In Baghdad, an official from the Ministry of Interior confirmed the attack, saying seven police, including one officer, were killed.

IS seized large swathes of Iraqi and Syrian territory from 2014, declaring a "caliphate" where they ruled with brutality before the jihadists' defeat in late 2017 by Iraqi forces backed by a US-led military coalition.

IS lost its last Syrian bastion, near the Iraqi border, in 2019.

The US-led anti-IS coalition continued a combat role in Iraq until December last year, but roughly 2,500 American soldiers remain in the country as trainers.

IS remnants, however, remain active in several areas of Iraq.

Baghdad's security forces continue to carry out counter-terrorism operations against the group and the deaths of IS fighters in airstrikes and raids are regularly announced.

Despite the setbacks which has left IS a shadow of its former self, the group can still call on an underground network of between 6,000 and 10,000 fighters to carry out attacks on both sides of the porous Iraqi-Syrian border, according to a UN report released earlier this year.

On Wednesday a roadside bomb that hit a military vehicle killed three Iraqi soldiers in farmland north of Baghdad, the defence ministry said.

There was no immediate claim for the bombing in a known hotpsot of IS sleeper cells.

Last month a machine gun attack on a remote northern Iraqi military post killed four soldiers near Kirkuk, a military source said. There was no immediate claim of responsibility.

In January 2021, IS claimed responsibility for a twin suicide attack at a Baghdad market that killed 32 people, the first such assault in the city for more than three years.