WASHINGTON/ISLAMABAD, 4 November — Afghanistan’s ruling Taleban yesterday said they had shot down a US helicopter and downed another US aircraft which came to its aid, killing up to 50 troops. The US central command dismissed the reports. An Information Ministry official said the Taleban shot down the second aircraft in Nawoor district of Ghazni province at around 11 p.m. (1830 GMT Friday) while it was trying to rescue crew of another that had crashed in the area. "No US helicopters were shot down in Afghanistan," CNN quoted the US Central Command as saying.

In Islamabad, the Taleban ambassador to Pakistan said that due to heavy snow and the remoteness of the area it was still not clear whether one of the aircraft was a plane or a helicopter. "It’s a very huge plane. We do not know the model," ambassador Mulla Abdul Salam Zaeef told reporters, adding that the aircraft appeared to have had four propellers and debris was scattered over a wide area. "Of course, all the people would have been killed."

There was no independent confirmation of the report. "We believe some bodies may still be in the area," he said. Because of heavy snow our Mujahedeen (holy warrior) brothers are finding it hard to find the bodies. They may be covered by snow."

In Kabul, the official said between 40 and 50 Americans had died in the helicopter crash. "You can see the bodies of the Americans on board the helicopters with their uniforms," Zaeef said.

A US helicopter on a special forces mission in Afghanistan crashed in bad weather at about 1830 GMT on Friday, injuring four crew members, but all were rescued and evacuated from the country, the Pentagon said. "As we stated from day one, we don’t respond to Taleban claims because more often that not, they turn out to be false," Pentagon spokesman Lt. Col. Dan Stoneking said. Pressed further, all Stoneking would say to counter the Taleban report was that the Pentagon’s statements on Friday evening about the crashed US helicopter "speak for themselves".

The Taleban ambassador said that seven US helicopters and planes had been shot down since the start of US airstrikes in Afghanistan a month ago. Among them, said the ambassador, was a helicopter and plane shot down at the weekend with a major loss of US lives. Zaeef’s figure for the number of US planes downed was the highest given yet by the Taleban. "Seven helicopters and planes have been shot down, one cannot estimate the number of crews on these helicopters and planes," he told reporters at his Islamabad residence.

In a recorded video address, Bin Laden attempted to capitalize on anger at the civilian casualties of the US bombardments and stir up Muslims against the regimes which are aiding the US manhunt. "The Afghan people have nothing to do with this, but the campaign is continuing, exterminating villagers and civilians, women, children and innocent people, with no right to do so," he said.

In the statement, broadcast on Al-Jazeera satellite television, Bin Laden attacked the United Nations.

"Those who want to solve our problems at the UN are hypocrites; our suffering is caused by the UN," he said, asking: "Who issued the Palestine partition resolution in 1947? The United Nations." He said the Afghan people were not to blame for the Sept. 11 attacks. "Today without any evidence the United Nations is issuing resolutions in support of America... against the weak who only recently emerged from a devastating war waged by the Soviet Union," Bin Laden said.

"We have suffered and continue to suffer because of the UN, and no Muslim should turn (to the UN) because it is an instrument of crimes," he said. "We (Muslims) are being slaughtered every day and it (UN) does not lift a finger," Bin Laden charged.

Afghan opposition forces backed by US air power claimed they had scored a major victory against the Taleban yesterday as the loss of a US helicopter underscored the danger of the looming Afghan winter. US warplanes continued bombing targets in Afghanistan. Qari Qudratullah, a spokesman for Northern Alliance commander Muhammad Atta, told AFP by telephone that 800 Taleban fighters had switched sides allowing the alliance to overrun a key district south of Mazar-e-Sharif.

If confirmed, the advance would be the opposition’s first major success since small teams of US commandos joined their ranks and US bombers began carpeting Taleban positions with powerful bombs. There was no independent means of confirming the Alliance claim, but a Taleban spokesman in Kabul admitted there had been fighting in the region.

US F-18 fighter jets bombed the village of Es Takh Kherch on the front line north of the capital Kabul for three hours, an AFP reporter saw, as strikes continued on Taleban positions defending the capital. More US strikes were directed at Taleban positions in the far north of the country near the border with Tajikistan. The United States launched its campaign against Afghanistan in a bid to hunt down Bin Laden and his Al-Qaeda network of Islamic extremists, whom it blames for the Sept. 11 attacks on US cities that killed an estimated 5,000 people.

In addition to helping the Northern Alliance, the US-led anti-terror coalition has also been encouraging efforts by Afghan leaders loyal to exiled King Muhammad Zahir Shah to foment a rebellion in the south of the country. But those efforts, already reeling from the capture and execution of guerrilla hero Abdul Haq, received a second blow Thursday when Taleban troops ambushed Hamid Karzai, a former Afghan minister on a mission for the king.

In south Afghanistan the Taleban hanged three of 25 supporters of Karzai captured in an attack on the opposition leader’s camp, the Pakistani-based Afghan Islamic Press reported yesterday. The agency, quoting its own unidentified sources, said the men were hanged on Friday. There was no independent confirmation of the report. "All three men were hanged on Friday at Dehramad in Uruzgan (province)," it said.

Karzai, 46, a deputy foreign minister in a pre-Taleban government, fled to the hills after Taleban fighters attacked his camp in southeast Afghanistan where he was meeting tribal leaders to discuss a post-Taleban government.

The Taleban claim to have captured 25 of Karzai’s supporters during clashes in the Uruzgan province, which neighbors Ghazni, and to have hanged three of them. The envoy escaped, however.

"I think Karzai has been taken out of Afghanistan by American helicopters," Zaeef said. He said large amounts of ammunition had been captured and four of Karzai’s associates were killed in fighting on Friday.

But Karzai’s brother Ahmad Wali Karzai, who is in contact with the rebel’s party by telephone, told AFP he was still alive and inside Uruzgan.

As the fighting continued to raise tensions in Pakistan, President Pervez Musharraf said he would talk to US Defense Secretary Donald Rumsfeld today about halting the US strikes during the Muslim holy month of Ramadan. He added that "one should be very clear that it will have huge negative fall-out" if US bombardments continued after Ramadan begins on Nov. 17.

His appeal seemed likely to fall on deaf ears, however. On Friday at the White House, US President George W. Bush said: "The enemy won’t rest during Ramadan and neither will we."

Bush assured Americans yesterday that bio-terrorists would be brought to justice amid indications that the public is losing faith in his administration’s response to the anthrax scare.

A month after the first of four people died from anthrax infection, Bush admitted in his weekly radio address that thousands of law enforcement officers had failed to come up with a plausible lead about who is behind the attacks.

"We do not yet know who sent the anthrax — whether it was the same terrorists who committed the attacks on Sept. 11, or whether it was the — other international or domestic terrorists," Bush said. He dangled a one-million-dollar reward for any information leading to a resolution of the investigation.

"If you see anything suspicious, or have useful information, please contact law enforcement authorities.

The Postal Service and the FBI have offered a reward of up to one million for information leading to the arrest and the conviction of the anthrax terrorists," he said.

A new poll showed that Americans spooked by the widening bio-terrorism scare that has killed four and infected a total of 17 are no longer convinced Bush and his White House team are on top of the anthrax outbreak.

Asked whether they thought Bush had a solid plan for fighting bio-terrorism and other terrorist threats, Americans were split down the middle, according to a poll in Newsweek magazine, which goes on sale Monday.

The poll said 46 percent of Americans believe the president’s approach is ineffective, down from 48 percent in the same poll a week ago, and compared to 46 percent who believe otherwise.

Bush has recently defended the administration’s often vague warnings about "credible" threats to come that have triggered panic in some areas.

Last week, security at the four bridges in California including San Francisco’s famous Golden Gate Bridge was stepped up in what critics charged was an overreaction to a purported terrorist threat.

But Bush insisted yesterday that the administration would continue to issue warnings when they were considered justified.