Human Rights Watch (HRW) says CIA-backed Afghan paramilitary forces have "committed summary executions and other grave abuses without accountability" -- including extrajudicial killings, forced disappearances, and attacks on health-care facilities.
In its report, released on Thursday, HRW called on the Afghan government to immediately disband all pro-government paramilitary groups that operate outside the "ordinary military chain of command."
It is also calling for the Afghan government to "impartially investigate all allegations of abuse by Afghan security forces" and to "prosecute those responsible for war crimes and serious abuses."
It says both the United States and the Afghan government should also "cooperate with independent investigations of all allegations of war crimes and other human rights abuses."
It also says the U.S. government should "investigate any U.S. personnel" involved in abuses, and should "cease supporting Afghan forces that have been responsible for serious violations."
HRW documented 14 cases from late 2017 to mid-2019 in which it said CIA-backed "strike groups" committed grave abuses during night raids, such as one in the southeastern province of Paktia in which a paramilitary squad killed 11 men, including eight who were home for the Eid holidays.
In some cases, HRW says, troops detained men and didn't tell families where they were being held.
The U.S. Central Intelligence Agency has disputed the HRW report, saying many of the claims against Afghan special forces were "likely false or exaggerated."
"In ramping up operations against the Taliban, the CIA has enabled abusive Afghan forces to commit atrocities including extrajudicial executions and disappearances," said Patricia Gossman, the report's author and HRW's associate Asia director.
"In case after case, these forces have simply shot people in their custody and consigned entire communities to the terror of abusive night raids and indiscriminate air strikes," Grossman said.
Night raids, which combine surprise, overwhelming firepower, and night-vision equipment, are a tactic preferred by special forces.
On several occasions, raids which usually take place in Taliban-controlled areas were backed by airstrikes that "indiscriminately or disproportionately" killed civilians, HRW said.
According to data released this week by NATO, the United States conducted 1,113 air and artillery strikes in September, a large increase on previous months that came as talks between Washington and the Taliban collapsed.
CIA spokesman Timothy Barrett said the agency's operations abroad are conducted in "accordance with law and under a robust system of oversight."
Barrett accused the Taliban of spreading misinformation and noted that the militants do not operate under any similar rules.
"Unlike the Taliban, the United States is committed to the rule of law," officials added in a CIA statement.
"We neither condone nor would knowingly participate in illegal activities, and we continually work with our foreign partners to promote adherence to the law."
Afghanistan's CIA-backed militias, whose tradition goes back to the Soviet-Afghan war of the 1980s, are seen as a critical tool in the fight against Taliban and Islamic State militants.
Such paramilitary groups are officially under Afghanistan's National Directorate of Security (NDS) but often operate almost independently of Afghan authorities.
Speaking to HRW, one unnamed diplomat referred to them as "death squads."
The NDS did not immediately comment.
The Special Inspector General for Afghanistan Reconstruction (SIGAR), a U.S. government monitor, says Afghan special forces conducted 2,531 ground operations from January-September this year, more than the total of 2,365 for all of last year.
A U.N. report earlier this month said 1,174 civilians were killed and 3,139 wounded in Afghanistan from July to September this year -- a 42 percent increase over the same period last year.