KABUL - The Taliban said Saturday they had killed "Christian missionaries" working in remote northern Afghanistan where the bullet-riddled bodies of six Americans, one German and a British national were found.

Three women were among the group of foreign eye doctors working for the aid organisation International Assistance Mission (IAM), said its executive director Dirk Frans.

"Five men, all American, and three women, an American, German and Brit were killed," Frans told AFP.

Head of Badakhshan provincial police Aqa Noor Kintoz said the group had been lined up and shot in dense forest, according to the testimony of a sole Afghan survivor. The Taliban later claimed responsibility.

"Yesterday at around 8am, one of our patrols confronted a group of foreigners. They were Christian missionaries and we killed them all," said Zabihullah Mujahed, a spokesman for the Taliban.

Frans corrected the police chief of northern Badakhshan province who earlier said six Germans and two Americans were among the dead.

The US Embassy said it still could not confirm the number of US fatalities but said it had reports of "several" Americans among them.

IAM, whose annual report says its headquarters are in Kabul, says it provides the majority of eye care available to Afghans, running eye hospitals in Kabul, Herat, Mazar and Kandahar.

The Taliban spokesman said the group had been lost in the forest and were killed as they tried to escape.

"They were carrying Persian language bibles, a satellite-tracking device and maps," he said.

Kintoz said they were shot by armed men in a remote area of Badakhshan province, according to the testimony of "Saifullah", an Afghan who survived.

The group of eight ophthalmologists had been travelling with three Afghans between Badakhshan and Nuristan provinces and spent a few nights in the forest, he reported Saifullah as saying.

"On the last day they were confronted by a group of armed men who lined them up and shot them. Their money and belongings were all stolen," said Kintoz.

He said that according to Saifullah`s testimony he had escaped death by reading verses of the Koran, prompting the men to realise he was a Muslim and release him in neighbouring Nuristan province.

The police chief said local villagers had warned the group not to enter the dangerous forested area, but they had insisted they would be safe because they were doctors, according to Saifullah`s statement.

He said the bodies had been found in Kuran wa Minjan district, an area on the border with Nuristan province, one day`s drive from the provincial capital Faizabad.

A US Embassy spokeswoman said "several" American citizens were believed to be among the dead, found on Friday, but could not give further details.

"We have reason to believe that several American citizens are among the deceased.... (We) are actively working with local authorities and others to learn more about the identities and nationalities of these individuals," the spokeswoman said.

The British Foreign Office said it was "aware of reports and (we) are urgently looking into it".

There was no immediate response from German authorities.