Human Rights Watch (HRW) says the US Special Forces have been complicit in February's torture and killings of Afghan civilians in the troubled Maidan Wardak Province.
The rights group raised fresh questions in a recent report about the role of US Special Forces in the deaths of several men in Wardak's Nerkh district in late 2012 and early 2013.
"While it is clear that crimes occurred, US authorities need to establish what exactly happened and who is responsible," the rights group said in a statement on Thursday.
Meanwhile, senior provincial Afghan officials say they have detained a number of US agents who have been seriously involved in torturing and killing of Afghan citizens. Evidence shows the suspects alongside American forces have committed torture and multiple crimes against civilians in the troubled region.
Afghan investigators have recently found substantial proof that American Special Forces have been involved in kidnapping, torturing, and killing of Afghan civilians in the volatile province.
The developments came after locals complained to human rights groups of being terrorized in recent months by US commandos and armed Afghan irregulars working with them.
Local residents said hundreds of families had left their homes due to harassment and torture by US-backed military units in the province in recent months.
The US-backed NATO command has for months ignored residents’ complaints of severe abuses committed by the elite American troops.
Afghan President Hamid Karzai ordered US Special Forces to immediately withdraw from the violence-wracked province after investigators revealed evidence of torture and killings.
Karzai has also prohibited his armed forces from requesting NATO airstrike support. Hundreds of Afghan civilians have been killed in several US-led airstrikes in various regions of Afghanistan over the past few months.
Civilian casualties have long been a source of friction between the Afghan government and US-led foreign forces and have dramatically increased anti-US sentiments in Afghanistan.
The United States and its allies invaded Afghanistan in 2001 as part of Washington’s so-called war on terror. The offensive removed the Taliban from power, but insecurity remains across the country despite the presence of thousands of foreign troops.