Suspected insurgents killed at least 17 police officers and freed 33 prisoners during a daybreak attack on a police station in Iraq on Tuesday, police said.

Police said more than 20 gunmen in five civilian cars arrived at dawn at the station in the city of Muqdadiyah, north of Baghdad.

They lobbed a mortar round at the station, then stormed it on foot, firing automatic rifles and rocket-propelled grenades. At least 17 police officers and a guard at a neighbouring courthouse were killed in the fighting. Ten of the attackers were also killed, police said.

The police station in Muqdadiyah, where suspected insurgents killed at least 17 police officers and released 33 prisoners on Tuesday. (AP Photo/Mohammed Adnan)

The attackers set the police station on fire and detonated a series of bombs as they made their escape.

The attack left 13 others wounded, including police officers and civilians.

Most of the freed prisoners were suspected insurgents.

A woman is questioned at a checkpoint in Muqdadiyah after Tuesday's attack. (AP Photo/Mohammed Adnan)

Muqdadiyah is about 95 kilometres northeast of Baghdad in the Sunni heartland.

• FROM MARCH 19, 2006: Killing continues on Iraq invasion's third anniversary

On Monday, at least 39 people were killed in Iraq by insurgents and sectarian gangs.