Human Rights Watch is calling for a "thorough and impartial investigation" into allegations that U.S. Special Forces were complicit in the torture and killings of Afghan civilians in Wardak Province.
The rights group said a report published in "Rolling Stone" magazine on November 7 raised fresh questions about the role of U.S. Special Forces in the deaths of 18 men in Wardak's Nerkh district in late 2012 and early 2013.
Andrea Prasow of HRW said in a statement that "while it is clear that crimes occurred, U.S. authorities need to establish what exactly happened and who is responsible."
An Afghan interpreter has been detained by U.S. forces over the killings, but he has alleged that he was following American orders.
U.S. Special Forces withdrew from Nerkh in April.
With reporting by AFP