NATO said Tuesday two of those killed Monday night were later identified as ‘known insurgents’, but Karzai and the provincial chief of police, Abdul Hakim Hesaq Zoy, said they were all civilians and one of the victims was a 12-year-old boy.

Lt. Col. Todd Vician, a NATO spokesman in Kabul, said the four were found to be unarmed. He added the military concluded two of the men were insurgents based on information found in the military's bio-metric database.

NATO released a statement saying the car kept accelerating toward the military convoy despite attempts to flag the vehicle down by flashing lights and firing warning shots.

Mr Karzai said in a statement he "condemns the shooting of civilians by international forces." "This act goes against the commitment of the international forces in Afghanistan to protect the people and fight against terrorists," he said.

The UN has called for better protection of Afghan civilians after the death toll rose last year to its highest level since the 2001 fall of the Taliban regime.

AP