The bombing targeted General Abdul Raziq, the Kandahar provincial police chief, who has a strong anti-Taliban background. Raziq survived the bombing with "minor" injuries to his face, arms and a leg.

"His injuries are not serious and he will soon be discharged from the hospital," a statement from the provincial governor's office said.

"He suffers from burns on his face, arms and leg, it's not serious," Jawed Faisal, a spokesman for the provincial administration, told AFP.

Faisal said four civilians were killed and about 20 others, mostly civilians and members of the same family, were wounded in the blast.

The spokesman described the explosion as "massive, very, very huge". He said the truck bomb was detonated by a suicide attacker as the vehicle of the police chief passed through a neighbourhood in Kandahar city.

There was no immediate claim of responsibility for the bombing but Taliban insurgents regularly use suicide attacks against the Afghan government and its Western military backers.