No casualties were reported, but a statement made by a NATO official suggested there might have been some injuries or deaths.
Since it was early in the morning, there were not a lot of people around. Otherwise, it could have caused a lot more casualties,'' the official told the BBC.
A bomb placed under one of the vehicles caused a chain reaction as the trucks were parked close together. Such attacks on military supplies are common in Pakistan, but they are less common in Afghanistan, where equipment and supplies tend to be heavily guarded.