A total of 31 members of the US Special Forces have died in a helicopter crash in eastern Afghanistan along with seven Afghans, a statement from Afghan President Hamid Karzai's office said Saturday.
"The president of the Islamic Republic of Afghanistan Hamid Karzai expressed condolences over a NATO helicopter crash and the deaths of 31 members of US special forces," the statement said.
The crash late Friday represents the biggest death toll in a single incident for international forces in Afghanistan since the start of the war in 2001.
Seven Afghans were also killed in the crash, the statement said, taking the total death toll in the incident to 38.
The Afghan defence ministry said they were also special forces.
"This helicopter crashed in Wardak province last night, as a result of which including the crew members, 31 personnel of American special forces lost their lives," the presidential statement said.
"In this incident, seven Afghan forces were also killed.
"The president of the Islamic Republic of Afghanistan expresses his sympathy and deep condolences to US President Barack Obama and the family of the victims."