A huge blast destroyed several shops and houses in Kabul early today, killing at least four people, police said.
Afghan officials gave conflicting initial information about the cause.
Deputy city police chief Zulmay Khan said the explosion was caused by gunpowder in shops selling ammunition for hunting rifles.
Ali Shah Paktiawal, the criminal director of Kabul police, said it was a car bomb, and had killed at least four or five people.
At least three others wounded, covered in dust and cuts, were pulled from the rubble of collapsed mud-brick buildings and put into waiting ambulances.
People used their hands to dig for more people feared trapped.
The blast threw piles of burning wreckage into the street and windows were shattered for hundreds of metres around.
One car was overturned, but it did not appear to have been the source of a bomb.
Most of the shops were shut at the time of the blast, around 6.30am (2am Irish time), in part of the city
where many buildings are still ruined from years of conflict.
Khan said most of the casualties were caused by houses collapsing in the explosion.