Police in Iraq say ISIS militants fired mortar rounds at a soccer field near a Shiite shrine on Saturday, killing six civilians and wounding nine others.
The attack occurred in the village of Daquq, in the northern Kirkuk province in Iraq, as people were exercising.
Police officials confirmed the attack, speaking on condition of anonymity in line with regulations.
The area of the attack, southeast of the city of Kirkuk, is controlled by Iran-supported militias known as the Popular Mobilisation Forces.
ISIS, which once ruled a self-styled caliphate sprawling across Iraq and Syria, no longer controls territory in either country but has continued to stage sporadic attacks.
The group claimed responsibility for an attack on a Shiite mosque south of the capital Baghdad on Friday, which killed three people and injured 34. After a motorcycle rigged with explosives detonated on a commercial street in the village of Mussayyib, ISIS said it had targeted a "gatherings of Shiites".