The international rights group is accusing Iraqi security forces of picking up villagers suspected of having links to Daesh before torturing and killing them.
International rights group, Amnesty International, has said that Iraqi government forces allegedly tortured and killed villagers south of Mosul, where a US-backed military operation against Daesh is in progress.
The report said security forces picked up groups of men in separate incidents, on or around October 21, on suspicion of ties to Daesh. They were then beaten with cables and rifle butts before being shot to death. In one case, a man's head had been severed from his body.
"Men in federal police uniforms have carried out multiple unlawful killings, apprehending and then deliberately killing in cold blood residents in villages south of Mosul," said Lynn Maalouf, deputy director for research at Amnesty's Beirut office.
The report said victims included up to six people who were found last month in the Shura and Qayyara sub-districts of Mosul, the second largest city of Iraq seized by Daesh in 2014.
Amnesty warned that without accountability, the alleged abuses could be repeated in other towns and villages as the Mosul offensive continues.
HRW warns about risks of violations
In a separate report, Human Rights Watch (HRW) said at least 37 men suspected of being linked to Daesh had been detained by Iraqi and Kurdish peshmerga forces.
Relatives said they did not know where most of the men were being held and had not been able to contact any of them while in detention, according to the report.
HRW warned that such conduct "significantly increases the risk of other violations," including torture.
Iraqi Interior Ministry denies violations
An official from Iraq's Interior Ministry denied there had been any violations. He says Iraqi forces are respecting human rights and international law.
A spokesperson for the Kurdish regional government, Dindar Zebari, denied the HRW report, saying any delays in informing families were due to limited resources.
"Nobody has been kept in unknown facilities. They are kept in identified facilities," Zebari said.
The Mosul operation, backed by US-led air strikes, involves a 100,000-strong alliance of troops, security forces, Kurdish peshmerga and Shia militias.