A senior Afghan politician has paid tribute to the medical team shot dead in the country's north-east last week.
Dr Abdullah Abdullah, a former presidential candidate who trained as an eye surgeon with one of the medical workers, told the BBC they had been devoted to helping Afghanistan's needy.
He said it was shocking that they had been killed in such a way.
The Taliban said they carried out the ambush, but police said they believed robbery was the motive.
US Secretary of State Hillary Clinton has condemned the killings as a "senseless act" against "heroic, generous people".
Eight foreigners and two Afghans were found shot dead next to abandoned vehicles in Badakhshan province on Friday, days after they had lost contact with their base.
The foreigners - six Americans, one Briton and a German - worked for the International Assistance Mission (IAM), a Christian charity providing eye care and medical help.
The police say one of the team's Afghan drivers has been arrested on suspicion of helping the armed men.
The bodies of the dead medical workers have been taken to Kabul and have been formally identified, although US officials said they would not release their names out of respect for their families.
Zabihullah Mujahid, a Taliban spokesman, said they were missionaries and claimed that bibles translated into Dari had been found.
But Dr Abdullah dismissed the Taliban's claims as "ridiculous".
He said he had trained with the medical team's leader, Tom Little, an optometrist from New York who had lived and worked in the country since the 1970s.
"These were dedicated people. Tom Little used to work in Afghanistan with his heart - he dedicated half of his life to service the people of Afghanistan.
"To hear that he was killed... in such a brutal manner - I couldn't believe it."
He labelled the attackers "enemies of the Afghan people", and said he hoped the incident would not deter aid groups from their work.
In a statement, Mrs Clinton described the killings as a "despicable act of wanton violence" against people who were in Afghanistan "to help people in need".
"We condemn in the strongest possible terms this senseless act," she said. "We also condemn the Taliban's transparent attempt to justify the unjustifiable by making false accusations about their activities in Afghanistan."
Badakhshan, populated mainly by ethnic Tajiks, is one of the few provinces not to have been controlled by the Taliban before the US-led invasion of 2001.
Analysts say it has long been regarded as a safe area, although locals have complained about the growing threat from insurgents.
IAM said its eye camp team had been working for the past two-and-a-half weeks in the neighbouring province of Nuristan at the invitation of communities there.
The charity said the team had been returning to Kabul through Badakhshan because they thought that would be the safest route.
IAM said it lost contact with them on Wednesday evening, after which their convoy is thought to have come under attack.