United Nations officials say that the head of the UN refugee agency, Ruud Lubbers, has secured the agreement.

Mr Lubbers who was in the northern city of Mazar-i Sharif, met several factional leaders including Abdul Rashid Dostam and Atta Mohammed whose forces have been engaged in factional fighting.

Ethnic Pashtuns living in northern Afghanistan have complained of harassment, and as a result thousands of them still in refugee camps in the south have been reluctant to return to their homes in the north.

The fighting has also disrupted the provision of aid to northern Afghanistan. Mr Lubbers is due to travel on to the region of Nahrin, in Balkh province, which was hit by a series of earthquakes last year.