At least 25 people, all but one of them women and children, were killed when a bus caught fire after being hit by a car in the northern Iraqi city of Kirkuk on Saturday, a police chief said.

The families were travelling on the bus from Baghdad to the northern Kurdish province of Dohuk when the vehicle got stuck in a pothole, according to Kirkuk province police chief Major General Jamal Taher Bakr.

Before it could be moved, a car crashed into the side of the bus, starting a fire. The bus's automatic doors did not open, trapping its passengers inside.

Of the 25 dead, 24 were women and children from the bus. The driver of the car was also killed. Seven other people were wounded, including the bus driver and five passengers.

"This is one of the most horrible accidents in Kirkuk's history," Bakr said.

Five police killed in twin Baghdad blasts
Baghdad (AFP) Aug 27, 2011 - Twin roadside bomb blasts in east Baghdad killed five policemen and wounded seven other people late on Saturday, an Iraqi interior ministry official said.

The explosions targeted a police patrol in the Ghadeer neighbourhood, the official said, on condition of anonymity. Of the seven wounded, three were police and the others civilians.

Saturday's violence comes after Al-Qaeda's front group in Iraq threatened a campaign of 100 attacks, starting mid-August, to avenge the death of Osama bin Laden in a US special forces raid in Pakistan on May 4.

Violence is down across Iraq from its peak in 2006 and 2007, but attacks remain common. A total of 259 people were killed in violence in Iraq in July, according to official figures, the second-highest figure in 2011.