Inside al Qaeda's mountain fortress

Anti-Taliban tribal fighters this morning inched their way through abandoned al Qaeda terrorist positions under the cover of devastating B52 carpet bombing with a small group of journalists, the first to gain access to part of Osama bin Laden's mountain redoubt.

Led by Haji Zaman, the main Mujahideen leader on the front line - making his own reconnaissance before launching an attack on the terrorists dug into caves in heavily forested ridges between us and the Pakistani border three miles away - we passed the detritus of a ferocious battle the day before.

Al Qaeda have been equipped with the latest 80mm Soviet mortars which lay scattered around in positions they abandoned only a few hours before we passed through. The approach to Tora Bora, a vast natural fortress reinforced with man-made caves, involved a dangerous drive through dusty foothills before we came within range of Bin Laden's mortar men at a switchback in the road 3,000 feet above the valley below.

Zaman ordered his men to scatter among the rocks and trees of the hillside as we crept forward towards the front line where his men had taken heavy casualties overnight. The Mujahideen are reluctant to discuss their dead and wounded but one confessed they lost up to 18 men when al Qaeda forces, mostly Arabs and Chechens, surrounded them. Another fighter said the 18 had not been left dead on the hillside but had been captured and were being held as hostages by the terrorists.

Whatever the truth, a heavy price has been paid for yesterday's initial successes for the Mujahideen when they overran what they described as the command centre of the terrorists' cave network. They may have underestimated the extent of Bin Laden's mountain lair but they were deeply respectful of the fighting skills of his men who have broken up into small teams and have repeatedly managed to ambush them, inflicting relatively heavy casualties on the Mujahideen guerrillas who traditionally expect to have the edge in mountain warfare.

While Zaman's fighters carried out their reconnaissance and their commander planned his next battle, the B52s bombed the higher ground in a series of ridges reaching towards the towering snowcapped White Mountain range which are the terrorists' only escape route. On the lower slopes the fleeing al Qaeda had clearly lived frugally, carrying only arms and ammunition. Abandoned infantry positions showed they are accomplished night fighters, leaving no traces of having used fires to cook while they concentrated their efforts on defending Bin Laden who the Northern Alliance is convinced has been hiding out in the Tora Bora complex.

"It's not easy. I'm going to go deep into Tora Bora to get as close as possible to see what to do next and then I will make my own plan," said Commander Zaman as he picked his way through the mountains of Tora Bora on foot.

Overnight, Bin Laden's men, defending his mountain lair, had forced Mujahideen fighters into a temporary withdrawal. B52s dropped cluster bombs on a network of Bin Laden's caves which remained in his hands on the other slopes of the Tora Bora area after the Mujahideen overran the network lower down.

The Mujahideen under Hazrat Ali reinforced their positions in the valley below Tora Bora in Muzaragh with an extra tank and an anti-aircraft cannon but held their fire in anticipation of US air strikes on the last of the major al Qaeda redoubts since the surrender of Kandahar started this morning.