KIRKUK, Iraq (AP) — Iraqi police say a massive Islamic State assault on targets in and around the northern city of Kirkuk has come to an end after a day and night of heavy clashes.

Brig. Gen. Khattab Omer said Saturday that all the attackers were killed or blew themselves up. The area around the provincial headquarters, where the fighting was heaviest, was quiet Saturday morning.

It was not clear how many militants took part in the assault, which appeared to be aimed at diverting attention from the IS-held city of Mosul, around 170 kilometers (100 miles) away, where Iraqi forces are waging a major offensive.

The militants killed 13 workers, including four Iranians, at a power plant north of Kirkuk, and a local television reporter was killed by a sniper in the city.