KABUL, Dec. 12 (Xinhua) -- Three Afghans were accidentally killed by NATO troops while the forces were patrolling in central Afghan province of Wardak province on Friday morning, said an alliance statement issued here.

    "A dismounted ISAF patrol observed a bus veering towards their patrol on the Kabul to Kandahar highway in Sayed Abad district. The patrol fired into engine block after the bus failed to stop under instruction," the statement said.

    It added that the patrol was forced to fire upon the bus in self-defense when the bus continued towards the patrol. "Three passengers in the bus were killed as a result."

    The Wardak governor and other governmental officials were notified about the incident by the senior ISAF commander for that area.

    More than 5,000 people have been killed so far this year in strife-torn Afghanistan despite over 70,000-strong international troops stationed here.