Fierce clashes erupted in the northern Iraqi city of Mosul Friday morning, killing three policemen and wounding nine others, a local police source and Iraqi television said.

Insurgents attacked police stations and patrols with car bombs, mortar rounds and machine guns early in the morning, prompting Iraqi security forces backed by U.S. troops to fire back, the source said.

Three policemen, including a police colonel, were killed and nine others, including a civilian, wounded in the clashes, the source added.

Explosions and gunfire resonated throughout the city early in the morning, while police chief of the city Maj. Gen. Wathiq al- Hamdani survived a car bomb attack, the source from the city's Security Operations Center told Xinhua on condition of anonymity.

The state-run television aired a brief interview with al- Hamdani, who said that the city was under control of Iraqi security forces.

Mosul, some 400 km north of Baghdad, has been a bastion of insurgency against U.S. and Iraqi forces since the U.S.-led invasion in 2003.

Source: Xinhua