KIRKUK: A car bomb detonated by a suicide attacker followed by gunmen storming a police headquarters in the north Iraqi city of Kirkuk killed 30 people and wounded 70 others on Sunday, a police general said.

Militants had apparently sought to take control of the compound, but were unsuccessful, Brigadier General Natah Mohammed Sabr, the head of the city's emergency services department, told AFP.

The deadly attack shattered a relative calm in recent days in Iraq, which has been grappling with a political crisis that has pitted Prime Minister Nuri al-Maliki against his erstwhile government partners amid weeks of protests calling for him to resign.

No group immediately claimed responsibility for Sunday's attack, but Sunni militants including al Qaeda's front group in Iraq frequently target security forces and government targets in a bid to destabilise the country and push it back towards the sectarian bloodshed that blighted it from 2005 to 2008.