Most of the prisoners belong to Taliban forces, say security sources from the volatile southern Afghan city of Qandahar where the men were being held.

The prisoners escaped through a tunnel they dug under the ground, the sources added. 

The correspondent said investigations are being carried out to clarify whether prison officials had helped the prisoners to escape.

General Salim, head of security in Qandahar, declined to say how the prisoners had escaped and said the incident was under investigation.

In late August, offcials said the jail on the outskirts of Qandahar, the former spiritual home of the ousted Taliban, was holding 50 to 60 "political inmates". The term is usually used to describe members of the Taliban. 

The Taliban have been blamed for a surge in violence across Afghanistan in recent months.

More than 300 people, including aid workers, US soldiers and Taliban fighters have been killed in firefights.