A mine-workers' camp in northern Afghanistan was attacked in the night - the Halo Trust said in a statement that an "unknown armed group" killed at least ten of its Afghan staff.
More than a dozen people were wounded.
The agency said there were 110 workers at the camp, and an official said that most of the survivors fled to nearby villages.
The interior ministry said the gunmen were Taliban insurgents, though the group denied involvement.
After decades of conflict, Afghanistan is strewn with mines and unexploded ordnance.
Agencies have been working to clear them in the years since the Taliban were ousted in 2001.
The Taliban frequently attack demining workers because, government officials say, the workers often help to defuse roadside bombs that insurgents have planted.