The corps affected is the first to be deployed in the field. Officials say another reason for men going absent is the difficulty they experience in dealing with their pay. Soldiers are paid around $75 a month - a good wage in Afghanistan - but the absence of a banking system prevents them from sending money to their families.

The 205th Corps of the Afghan National Army is based around the city of Kandahar. The south of Afghanistan has seen some of the fiercest fighting against remnants of the Taliban and their al-Qaeda allies. Members of the corps are in combat most days.

A U.S. military spokesman told the BBC News that around 300 men have deserted. That is one in 12 of the entire force.