A senior administration official says the helicopter that crashed Saturday carrying 31 U.S. special operations forces and seven Afghan soldiers was apparently shot down by insurgents in Afghanistan.
It was the highest number of American casualties recorded in a single incident in the decade-long war. The official spoke on condition of anonymity because the crash is still being investigated.
President Hamid Karzai sent his condolences to President Barack Obama, according to a statement issued by his office.
The Taliban claims to have brought the helicopter down with a rocket attack, but they have been known to make exaggerated claims in the past.
NATO says there "was enemy activity in the area."