The Islamic State group claimed responsibility for deadly suicide attacks on Friday in northern Iraq, the IS-affiliated Amaq news agency reported, as troops advanced on the jihadist bastion of Mosul.

"The forces of IS attacked the city of Kirkuk from all directions," Amaq said, after gunmen wearing suicide vests struck the main police headquarters and other government targets in the Kurdish-controlled city.

The jihadists also targeted a power plant being built by an Iranian company further north.