US renews assault on Tora Bora

Fighting on the ground has been intense

US forces have intensified their air strikes in eastern Afghanistan to try to dislodge al-Qaeda fighters from positions in the hills above the Tora Bora cave complex.

Anti-Taleban ground forces launched their own assault against the al-Qaeda fighters.

The offensive started after a second deadline for al-Qaeda to hand over their commanders passed with no sign of a surrender.

The latest fighting coincides with claims that al-Qaeda leader Osama Bin Laden is no longer in the area.

We do not hide in caves and do not run away from the confrontation. Suicide is our desire and our victory

Ayman al-Zawahri

The BBC's Damian Grammaticas, reporting from just behind the front lines, said the sound of US bombers could be heard throughout the day and there was no let-up in the attacks as night fell.

A senior anti-Taleban commander, Hazrat Ali, said the alliance initially met little resistance.

Later, however, his fighters came under heavy mortar and machine-gun fire.

The fighting is taking place in freezing conditions

Snow fell in the afternoon on the high slopes where the al-Qaeda fighters have been dug in.

Bin Laden's most trusted aide has meanwhile sought to quash speculation that the Saudi-born militant is among those holed up in the vast underground network of caves and tunnels, though insisting he remains in Afghanistan.

Ayman al-Zawahri, who is believed to have played a leading role in planning the 11 September attacks on the US, told the London-based magazine al-Majallah that he and other senior al-Qaeda leaders - including Bin Laden - would not "run away from Afghanistan".

"We do not hide in caves and do not run away from the confrontation. Suicide is our desire and our victory," he said in a telephone interview published on Thursday.

	Tuesday: About 800 al-Qaeda troops flee lower Tora Bora caves Wednesday: Al-Qaeda ignores 8:00am surrender deadline Thursday: B-52s resume strikes on Tora Bora US says there are indications that Bin Laden is still in region See also: Where is Bin Laden?

Mr Zawahri, leader of the Egyptian Islamic Jihad movement, also said that a female suicide bomber had killed two American servicemen - a report the Pentagon has denied.

The interview appeared to confirm that Mr Zawahri was not killed - as was first reported - by a US bombing raid last week in which several other members of his family are thought to have died.

Commander Ali had given the al-Qaeda fighters until Thursday morning to surrender and hand over 22 of their leaders - many of whom are wanted by the US.

In return, he had promised free passage for their subordinates.

A similar deadline passed on Wednesday without any sign of a surrender.