A small team of US soldiers was today still missing in the same eastern Afghan mountains where a special forces helicopter was shot down earlier this week.

The MH-47 Chinook helicopter came down on Tuesday while trying to help the reconnaissance team on the ground. All 16 US personnel on board the aircraft were killed.

The Taliban claimed to have shot down the helicopter, and US officers at the crash scene today said it appeared an unguided rocket-propelled grenade had hit the aircraft with a "pretty lucky shot".

US military spokesman Lieutenant Colonel Jerry O'Hara today said the missing team on the ground had not been in contact since shortly before the Chinook came down. "Every available asset" was being used in the efforts to find them, he said.

Another military spokesman told Reuters that, while US forces did not know the whereabouts of the team, they had no reason to believe its members had been captured or killed.

The spokesman said he could "not confirm or deny" a claim by a purported Taliban spokesman that insurgents had executed seven US "spies" before the helicopter was shot down in Kunar province, which borders Pakistan.

Mullah Latif Hakimi, the purported Taliban spokesman, also claimed rebels had captured a US soldier near the town of Asadabad in the area.

"One high-ranking American has been captured in fighting in the same area as the helicopter went down," he told the Associated Press. "I won't give you any more details now."

Reacting to the claim, Lt Col O'Hara said: "We have no proof or evidence indicating anything other than the soldiers are missing ... until we find our guys, they are still listed as unaccounted for and everything we've got in that area is oriented on finding the missing men."

Mr Hakimi, who said insurgents had shot down the helicopter, often calls news organisations to claim responsibility for attacks, sometimes giving information that proves to be either exaggerated or untrue. His exact ties to the Taliban leadership are not clear.

The loss of the 16 troops on the helicopter was the deadliest single blow to US forces in Afghanistan. The US led a coalition that ousted the Taliban in 2001 after the September 11 attacks on New York and Washington for harbouring Osama bin Laden's al-Qaida terror network.

US forces are fighting an escalating insurgency. Only eight months ago, Afghan and US officials hailed relatively peaceful presidential elections as an indication that the Taliban rebellion was finished.

However, remnants of the former Afghan regime have stepped up attacks, and there have been disturbing signs that foreign fighters - including some linked to al-Qaida - could be making a new push to create an Iraq-style insurgency.

The loss of the helicopter follows three months of unprecedented fighting that has killed around 465 suspected insurgents, 43 Afghan police and soldiers, 125 civilians and 45 US troops, including those who died in Tuesday's crash.

The bodies of the 16 personnel from the helicopter had been recovered and soldiers were trying to identify the remains, the US military said. The troops were killed in the crash and not during fighting on the ground after the helicopter had come down, a military spokesman added.

Rescuers - struggling against stormy weather, insurgents and the rugged terrain - reached the crash site yesterday, around 36 hours after the crash. Troops were still recovering parts of the aircraft today. The crash was the second time a Chinook helicopter has come down in Afghanistan this year. On April 6, 15 US service members and three US civilians were killed when their helicopter went down in a sandstorm while returning to the main US base at Bagram.

Earlier this week, the US president, George Bush, made a major speech trying to shore up domestic support for the conflict in Iraq, which he said had to be seen as part of the "war on terror" following September 11.