US-backed Afghan paramilitary groups arbitrarily kill civilians in overnight attacks and conduct enforced disappearances, Human Rights Watch said.
According to the organization, those Afghan groups supported by the "Central Intelligence Agency" (CIA) carried out executions without legal proceedings and committed other violations without accountability.
The organization accused the "strike forces" of attacks on health facilities on the back of alleged treatment of rebels.
The 50-page report documents 14 cases between late 2017 and mid-2019 in which Afghan strike forces committed serious abuses, some amounting to war crimes.
In one such attack in Paktia province in August, a paramilitary member killed 11 men in one village, the organization said.
"Witnesses confirm that none of these men showed resistance," Human Rights Watch said.
CIA-backed paramilitary groups have been active in Afghanistan since the war against the Soviet army in the 1980s.
The organization called on the United States to work with the Afghan government to disband and disarm all paramilitary forces operating outside the normal military chain of command, and to work with independent investigators to investigate all allegations of war crimes and other human rights violations.