KABUL/WASHINGTON, 14 December — US warplanes bombed the mountain hide-outs of Osama Bin Laden’s Al Qaeda fighters relentlessly yesterday as hopes of surrender went up in smoke and Afghanistan’s new government moved slowly into place. Afghan militia earlier ruled out any talks of surrender with Al-Qaeda.

The prime minister-designate arrived in the capital Kabul and was meeting Afghan leaders, solidifying the political collapse of the former Taleban rulers and their Al-Qaeda supporters.

According to the Afghan Islamic Press (AIP) agency, a ground assault against Al-Qaeda militants holding out in the Tora Bora mountain range appeared imminent after US helicopters landed special forces in the area.

Pakistan-based AIP said a flurry of helicopter activity was observed at Jalalabad’s airport in eastern Afghanistan overnight. Helicopters were seen heading toward Tora Bora, about 45 kilometers to the south.

Afghan allies of the US in the area told the news agency that at least three helicopters landed US troops at Agam, north of Tora Bora’s cave complex in the Spinghar mountains where Al-Qaeda fighters are holed up.

"It looks a ground attack is to begin," an Afghan fighter in the battle zone told the agency, recalling a similar attack on the complex in the 1980s by the occupying Soviet forces.

The hills and valleys near the eastern village of Tora Bora are home to networks of caves harboring an unknown number of Al-Qaeda fighters and possibly Bin Laden.

US planes, which continued to bomb relentlessly as night fell, have cornered the remnants of the movement in the barren region about 40 km south of Jalalabad.

Surrender talks fell apart on Wednesday and anti-Taleban fighters announced a new deadline that passed with no sign of gunmen coming down from the hills — suggesting the idea may have been a ruse.

"I heard an Al-Qaeda fighter say on the radio they don’t want to surrender," Haji Atiqullah, a spokesman for anti-Taleban commander Haji Zahir, told Reuters.

"They said ‘we want martyrdom, we will succeed.’ They won’t accept...I tried to talk to them but they did not want to."

Heavy cloud had made the US aircraft invisible, but they could be heard clearly. But when the clouds lifted, planes could be seen streaking through the night sky.

The narrow, pitted and twisting road to Tora Bora from Jalalabad was choked with traffic. Pickup trucks full of armed men traveled in both directions.

One Western security adviser familiar with the road said there were far more of the trucks than normal and speculated they might be preparing for a push on the Al- Qaeda hide-outs to follow up the US bombing.

Karzai arrived in Kabul from Kandahar, where he had overseen the surrender of the last Taleban stronghold.

He is due to take up his post as head of the interim administration on Dec. 22, under a UN-brokered accord signed by anti-Taleban leaders in Bonn.

Karzai met former President Burhanuddin Rabbani and other leaders in the presidential palace. He is staying at a guest house inside the sprawling palace compound.

Rabbani had complained foreigners imposed the government, from which he was excluded, but said he would back Karzai.

Karzai insisted that fugitive Taleban leader Mulla Muhammad Omar be tried. "He’s a criminal," he told the BBC. "...Look at the years of oppression, lack of economic activity, the killing, the murder, the destruction of property, destruction of values."

In Kandahar, gunmen took to the streets after Karzai left on Wednesday night, firing into the air, and worrying residents. "The situation is not good," one said.

Meanwhile, Pakistan dismissed a US newspaper report that Bin Laden had entered the country to escape the Tora Bora bombardment.

In Islamabad, a UN spokesman said hundreds of families had been forced to move. "Several hundred families are reported displaced from Tora Bora area due to the bombing campaign...the exact figure is difficult to obtain," he said.