Gunmen shot dead 10 Afghans working for a British landmine clearance charity in the country with links to Princess Diana and Prince Harry.
Sixteen local people were also injured in the attack on the HALO Trust camp in Baghlan province, in the north of the country, on Tuesday evening.
Sky News understands that no British or US nationals were injured or killed in the incident.
Afghan police blamed the Taliban for the bloodshed at a time of an escalating turmoil across Afghanistan as US and other foreign forces withdraw.
The HALO Trust, which facilitated Princess Diana’s famous minefield walk in Angola in 1997, described the assailants as “an unknown armed group”.
It said 110 men from local communities were in the camp when the attack happened at around 9:50pm local time – having finished their work on nearby minefield
“The group entered the camp and opened fire,” a charity spokesman said.
Provincial police spokesman Jawed Basharat gave more details.
“The Taliban brought them into one room and opened fire on them,” he said.
An official in the area said most of the surviving workers fled to nearby villages after the attack and police were working to help them.
A Taliban spokesman denied involvement but a senior government official in the capital, Kabul, dismissed the group’s comments, telling the Reuters news agency: “This was clearly execution by the Taliban.”
The militant group is fighting to topple the UK and US-backed Afghan government as long-running attempts at peace talks falter.
The Taliban frequently attack demining workers because, government officials say, the workers often help to defuse roadside bombs that the insurgents have planted.
Violence has sharply increased across Afghanistan since the United States announced plans in April to pull out all of its troops by 11 September.
The Taliban are fighting government troops in 26 out of 34 provinces, and the insurgents have recently captured more than 10 districts, government officials say.
The deteriorating security situation in Afghanistan is expected to feature at a summit of NATO leaders meeting in Brussels on Monday, including US President Joe Biden and British Prime Minister Boris Johnson.
In another incident, an Afghan army helicopter crashed in Wardak province, to the west of Kabul, on Wednesday, killing three crew members on board, the defence ministry said.
The Taliban said its fighters had shot the helicopter down but the ministry said the helicopter was trying to make an emergency landing after developing a technical problem when it crashed.
Afghanistan is strewn with mines and unexploded devices, with agencies still working to clear them 20 years after the Taliban was ousted in 2001.
The HALO Trust has been working there since 1988 and does similar work in 19 other countries, employing 9,000 staff.