"It was a suicide car bomb. There are many killed and wounded," police chief Shirku Shakir Hakim told AFP.

The car bomb went off just in front of the police academy in Al-Ihtifalat (Celebrations) Square in the southwest of the city at 3:45 pm (1145 GMT)," Hakim said.

Kirkuk, with its mosaic of Kurds, Arabs and Turkmen, is a frequent target of roadside bombings and shootings, as insurgents seek to upset the delicate ethnic balance in the city.

Meanwhile, thirteen Iraqis were killed and 53 wounded in heavy clashes between US forces and insurgents in Tall Afar while twelve policemen were killed in a joint US-Iraqi offensive in Latifiya.

Dr. Fawzi Ahmed, from the local district hospital in this mainly Shia Turkmen town, said 13 Iraqi civilians had been killed and 53 wounded.

The US Army reported three of its troops wounded and the Iraqi National Guard two.

Witnesses and police said the fighting broke out at around 8:30 am (0430 GMT) when US forces, backed by national guard troops, surrounded two neighbourhoods and started carrying out house-to-house searches.

Columns of smoke filled the sky as insurgents lobbed mortar rounds and fired Kalashnikovs in response to the US armoured vehicles, warplanes and helicopter gunships, an AFP reporter witnessed.

The US Army's 2nd Infantry Division entered the city at 8:00 am (0400 GMT) to hunt down a "terrorist cell" and detained one wanted individual, the military said.

"The city of Tall Afar has been a suspected haven for terrorists crossing into Iraq from Syria," it charged.

Amid heavy fighting, an aircraft dropped a one-tonne bomb near the city, the military acknowledged.

Soldiers killed two insurgents and detained 18, the US military said, adding that an OH-58D Kiowa helicopter made a controlled landing near Tal Afar after being hit by gunfire. None of the crew were seriously injured.

US forces left the town at around 2:00 pm (1000 GMT), but insurgents were hunkered down in their positions around Tall Afar for fear of a fresh assault by US and Iraqi government forces.

Twelve policemen were killed and five national guardsmen wounded Saturday in a joint US-Iraqi offensive on Latifiya, a haven for Sunni Muslim insurgents, an Iraqi national guard intelligence officer told AFP.

"Twelve policemen were killed and five national guardsmen wounded. Two hundred suspects were arrested in the Bass district in central Latifiya," the officer said on condition of anonymity, speaking from Mahmudiya, 20km from the trouble spot.

The towns of Latifiyah and Mahmudiya have long been under de facto control of the insurgents. Rebels have regularly assassinated police officers, raided stations and ambushed cars on the deadly stretch of road.

Two French journalists being held hostage by a radical Islamist group since August 20 disappeared while traveling the perilous route.

(AFP, AP)