Kabul - Afghan fighters chased Osama bin Laden's forces to "one last base" in the mountains on Tuesday, as the United States remembered those who died in the New York and Washington attacks exactly three months ago.

Tribal forces, aided by a rain of United States bombs, said they pushed diehard fighters from Bin Laden's al-Qaeda network into a final stronghold near Tora Bora.

"Bin Laden's supporters are now confined to one last base," said commander Mohammad Amin.

However, a spokesperson for the US-led coalition played down media reports they had offered to surrender.

Many think Bin Laden, accused of plotting the suicide airliner attacks and long protected by the routed Taliban, is making a last stand with his followers. But they cannot be sure.

The future was clouded too, by rising factional tensions in Afghanistan's second city Kandahar and officials here insisted foreign peacekeepers should play a limited role.

But for the United States and its allies, 8.46am in New York on December 11 was a time to recall the attacks three months earlier which triggered the superpower's wrath and sparked the Afghan war to track down Bin Laden there.

At the same minute as the first of two planes had struck New York's World Trade Centre, firefighters and officials at the site paid silent tribute to about 3 900 people who died there, at the Pentagon and aboard a fourth hijacked plane.

In Kabul, Northern Alliance defence minister Mohammad Fahim said a multinational force in the capital would be kept to 1 000 men and have a limited role and that his own forces would not withdraw.

The UN Security Council hopes to approve the force by Friday, but doubts lingered about whether it could be in place by December 22, when the new interim government takes over.

In the south, Kandahar bristled with ethnic Pashtun warriors demanding a greater share of power - a sign of how fragile the anti-Taliban alliance is once their common enemy has gone.

"There are lots of tribesmen standing by with weapons," said one witness. "They want a share in the new government."

One commander said Taliban and al-Qaeda fighters were still refusing to surrender at the city's Chinese hospital.

Hamid Karzai, due to become prime minister on December 22, stayed on in Kandahar to salvage a local power-sharing accord, instead of going to Kabul to meet UN envoy Lakhdar Brahimi, who arrived to help smooth the transfer of power. - Reuters