The battle for Tora Bora's peaks is gruelling
US Defence Secretary Donald Rumsfeld says hundreds of bombs have been dropped on the area over the weekend.
There he met Afghanistan's new interim leader, Hamid Karzai, who takes office on 22 December, and spoke to US troops.
Between 300 and 1,000 of Osama Bin Laden's followers are reported to be in the Tora Bora area, pursued by US and anti-Taleban Afghan forces, but Bin Laden's whereabouts are still a mystery.
Bin Laden's voice
An unconfirmed report from Washington says Bin Laden has been heard giving orders over a short-range radio in the Tora Bora mountains over the past week.
|
||
 |
See also: |
|
A US official, speaking on condition of anonymity, said it was confirmed "with reasonable certainty" that the voice on the radio was Bin Laden's, after it was compared with several videotapes.
The US blames Bin Laden for the 11 September attacks on the World Trade Center and the Pentagon.
The American troops are gathering documents and other potential evidence in the caves.
US special forces are also to test samples from an abandoned al-Qaeda training camp in southern Afghanistan for chemical, biological and radiation weapons material.
Mr Rumsfeld said the camp was on a list of sites to be searched.
"The take from it was particularly large and significant," he said.
In other developments:
Fighters surrounded
Al-Qaeda fighters are surrounded on three sides, and the only way out is up the mountains towards Pakistan.
It appears that some groups of militants are trying to take that route. A local Afghan spokesman told the BBC that 50 militants had moved out in groups of two or three on donkeys, crossing high mountain passes.
The BBC's Damian Grammaticas in the area says many al-Qaeda fighters have not been dislodged from the machine-gun positions and caves.
The Pakistani authorities say they have captured 31 foreigners suspected of belonging to al-Qaeda - mostly Yemenis - although the prisoners denied they came from the Tora Bora cave complex.
Mr Rumsfeld has said that, if captured, Bin Laden would be taken to a secure location and interrogated. President George W Bush would decide whether to prosecute Bin Laden in a military tribunal.
Kandahar prison
Space for up to 300 prisoners is being prepared at Kandahar airport, now controlled by US marines.
Mindful of the earlier uprising by prisoners in Mazar-e-Sharif, US forces are working to secure the area, sweeping it for mines and booby-traps.
Afghan forces have been trying to persuade Bin Laden's men to surrender.
One commander, Haji Hazir, said he believed he was close to convincing up to 300 fighters to lay down their weapons.
But he said the negotiations were complicated by the fact that he has demanded an unconditional surrender and the men are scattered across the mountains.
The International Red Cross is concerned at the treatment of captives and is seeking access to them.
Reports speak of mounting casualties among al-Qaeda's foreign militants, with one Afghan field commander telling Reuters he had seen 20 dead Chechens alone.