A coordinated early morning suicide bomb and gun attack on a police headquarters in Northern Iraq has killed at least 30 people and injured more than 70.

Nearby buildings were also damaged in the double assault. The area has been cordoned off to vehicles.

Reports suggest that Islamic militants made an unsuccessful attempt to take control of the police compound in the northern Iraqi city of Kirkuk.

So far, no group has claimed responsibility for the attack. Iraq's security forces and government buildings are a frequent target of Sunni extremists linked to al-Qaida.

The militants, who were heavily armed with guns and grenades, tried to enter the headquarters soon after the suicide car bomb went off. Witnesses told AFP that the insurgents were dressed as policemen and their vehicles were painted like police cars.

Before the attack, strife-torn Kirkuk had been enjoying a period of relative calm.