A car bomb attack on police headquarters in the southern Afghan city of Kandahar has killed at least nine people, including five policemen.

Some 19 others were wounded in the blast in a car park outside the police building, the local government said.

The blast -- thought to have been caused by explosives hidden inside a parked car and detonated remotely -- was strong enough to shatter nearby windows. Noone has yet said that they carried out the attack.  The explosion "took place near a busy shopping area", the provincial government said.

"It was a heavy explosion, it shook windows. There was gun fire for few minutes afterwards," said a local resident.

Children were reported to be among the dead and wounded.