An explosion has hit the eastern part of the Afghan capital and damaged at least two vehicles. There was no immediate word on casualties.

A witness says Monday's blast was a suicide attack on a convoy of foreign military vehicles.

Police and ambulances rushed to the scene near the Pul-i-Charkhi prison. Two civilian vehicles lay overturned and nearby shop windows were shattered from the force of the explosion.

A local shopkeeper named Jameel, who uses only one name, says he saw two NATO vehicles leaving the prison and a car slamming into the second one.

The alliance did not comment.

Taliban-affiliated militants have stepped up attacks in the final year of the international coalition's combat mission in Afghanistan, seeking to shake confidence in the Kabul government's ability to keep order.