The bombing happened at 1am yesterday in a village in the rugged and mountainous central region of Oruzgan, 105 miles north of the southern city of Kandahar.

Survivors of the attack said several guests had just fired their Kalashnikovs into the air, as is traditional in Pashtun wedding ceremonies. A US air patrol over-head wrongly concluded it was coming under fire and responded with devastating force.

An AC-130 helicopter gun-ship and B-52 bomber blasted the scene, leaving scores of people dead - among them women and children - and at least 40 injured.

Pentagon officials last night conceded that at least one bomb dropped on the village of Kakarak was "errant". But their initial response was confused and they were unable to explain why the pilots had failed to establish whom they were attacking in a region clearly abandoned by Taliban and al-Qaida fighters several months ago.

"There was no one to help last night," one resident, Abdul Saboor, said. "We managed to transfer some of the wounded to Kandahar in the morning. Some of the foreigners' choppers also came to help."

"There are no Taliban or al-Qaida or Arabs here. These people were all civilians, women and children."

An Afghan defence ministry official last night said more than 30 people had been killed in the attack, which appears to have gone on for two hours. The original death toll had been put as high as 120.

"It was a wedding ceremony and some of the participants were firing in the sky as part of the celebration. Americans have confessed that they made a mistake," he said.

Several survivors recovering in Kandahar's Mir Wais hospital yesterday said US troops had arrived at the scene shortly afterwards demanding to know "who fired on the helicopters".

Hospital officials said a number of wounded were being brought to Kandahar, a day's journey away by road. Most of the dead and injured were women and children, they said. A six-year-old girl named Paliko was brought to the hospital still wearing her party dress. She was injured, but villagers said all members of her family were killed.

"Their families are gone. The villagers brought these children and they have no parents. Everyone says that their parents are dead," Mohammed Nadir, a nurse, said.

The incident is deeply embarrassing for the American military, which has so far had little success in fulfilling its initial war aim of hunting down Osama bin Laden. Most senior Taliban figures together with remnants of al-Qaida decamped to Pakistan's tribal regions late last year, intelligence sources believe.

In Washington, the Pentagon yesterday admitted that at least one bomb dropped by western warplanes had missed its target, but it could not confirm claims that members of a wedding party had been killed.

Lt Cmdr Jeff Davis, a Pentagon spokesman, said anti-aircraft fire was directed at an air patrol of "coalition warplanes" and they had responded with close air support north of Kandahar. "At least one bomb was errant. We don't know where it fell," he said. "We are aware of reports of civilian casualties but don't know if casualties were caused [by] the bomb."

The Taliban's vanished leader Mullah Mohammed Omar grew up in the remote and overwhelmingly rural province of Oruzgan, which was once a Taliban stronghold. But with the demise of the fundamentalist regime last year virtually all locals with Taliban links escaped elsewhere. Spe cial forces and other coalition troops were in the area at the time of yesterday's incident, apparently searching for al-Qaida suspects.

American warplanes have made several other grievous errors during their war in Afghanistan - but are not believed to have killed so many civilians at a single stroke.

According to local Afghans, 11 members of a wedding party were killed in a similar incident in May in the village of Balkhiel, 30 miles north of the town of Khost.

The guests were bombed after celebrating by firing into the air. US officials later insisted their planes had come under enemy attack.

The village of Hazar Qadam wrongly bombed in January is also in Oruzgan. Some 16 innocent people were killed and 27 captured. The 27 were later released after US officials admitted their mistake and allowed them to return home.

In April four Canadian soldiers died when a US fighter bombed them by mistake during a training exercise.

And last December planes bombed a convoy from the eastern town of Khost, killing a group of tribal elders travelling to Kabul for Hamid Karzai's inauguration as interim leader.