Four Afghan civilians, including two children and a woman, were killed by U.S. forces in southern Kandahar city on Saturday, Reuters qouted a police official as saying. A U.S. military convoy opened fire on a vehicle, killing four passengers, Shah Agha, a Kandahar police official told Reuters. A statement from the provincial governor of Kandahar also confirmed the casualties. A spokesman for NATO in Afghanistan said three civilians were killed and two were wounded when NATO forces fired on a car because it failed to stop when repeatedly signalled to do so. The spokesman was unable to confirm if children were among the casualties or the nationality of the troops involved. U.S. Army General Stanley McChrystal, the new U.S. and NATO commander in Afghanistan, issued a directive in July stressing the importance of avoiding civilian casualties, which have undermined support for the war against the Taliban. -- SPA