An explosion apparently caused by a car bomb rocked eastern Kabul on Monday, according to witnesses, but no casualties were immediately reported.
The blast occurred near Kabul's main prison of Pol-e-Charkhi, the interior ministry said in a statement.
Witnesses told AFP the blast was caused by a car bomb targeting a foreign military convoy in the area.
An AFP photographer at the scene saw burnt and twisted parts of what seemed to be the vehicle carrying the bomb as well as a damaged armoured vehicle.
NATO and Afghan forces have cordoned off the area.
The NATO-led International Security Assistance Force (ISAF) said they were aware of an explosion but would not give any further details.
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