A suicide bomber detonated explosives near the entrance to a police building in the town of Dibis in Kirkuk province, and a second attacker was killed by security forces, police officers said.
Two more militants entered the police building and the local government headquarters, but were also subsequently killed, an officer and a local official said.
Dibis is located near the Bai Hassan oilfield northwest of the Kirkuk provincial capital, far from the areas of the province held by IS which overran large parts of Iraq last year.
Attacks in Kurdish-held areas of Kirkuk province that are behind the front lines have decreased compared with before the offensive, and Dibis had not been attacked for more than a year.