New US bombing outside besieged northern city

American warplanes are striking Taliban positions outside the northern city of Kunduz, the Islamic militia's sole remaining stronghold in the north of Afghanistan.

The city is under siege by Northern Alliance troops.

Defenders are thought to include thousands of foreign fighters loyal to Osama bin Laden, who are believed to be unwilling to surrender their positions.

In other Afghan cities, Taliban fighters last week retreated rather than face an attack from the Northern Alliance.

As the siege of Kunduz continues, the claim on the country's leadership by Afghanistan's ex-president , is causing diplomatic concern.

Burhanuddin Rabbani, returned to Kabul for the first time in five years. Mr Rabbani has never relinquished his claim to the presidency, though he has acknowledged international calls for a broad-based government.

UN Secretary-General Kofi Annan reiterated the importance of creating a broad-based government accepted by all of Afghanistan's diverse political and ethnic groups.

"If they do not do that, and one group tries to control power and assert itself, it is going to be a problem down the line," he said in Ottawa after meeting with Canadian Prime Minister Jean Chretien.

"And I would hope that Mr. Rabbani also is aware of this happening since he knows intimately the history of his own country."