Islamic State (IS) militants have ambushed a group of Iraqi paramilitary fighters, killing at least 27, officials say.
The attack came two months after Baghdad declared victory over IS in all of Iraq.
The Popular Mobilization Forces, an umbrella group of mainly Shi'ite militias, said in a statement that the attack took place on February 19 in the Hawija region, some 300 kilometers north of Baghdad, while the paramilitaries were conducting overnight raids.
The attackers were disguised in army uniforms and pretended to man a fake checkpoint, the statement said.
The fighting lasted for at least two hours and some of the militants were killed while others fled the area, it said.
IS claimed responsibility for the attack in a statement on its Amaq news agency.
In December, Iraq declared total victory over IS in all of Iraq, after more than three years of fighting. But Iraqi and U.S. officials have warned IS would continue with insurgent-style attacks.
Last month, IS launched suicide bombings in central Baghdad, killing at least 38 people.