An Iraqi army division trained by the U.S. military allegedly assassinated several dozen prisoners in the final days of battle to recapture Mosul's Old City from Islamic State, according to Human Rights Watch.
The rights group, in a report issued Thursday, is urging the U.S. to end support for the Iraqi army's 16th Division pending a probe into what it believes are war crimes.
"The U.S. military should find out why a force that it trained and supported is committing ghastly war crimes," said Human Rights Watch Middle East director Sarah Leah Whitson. "U.S. taxpayer dollars should be helping to curtail abuses, not enable them."
The watchdog said the alleged executions were witnessed by two international observers. The observers said they saw a group of Iraqi soldiers who identified themselves as members of the 16th Division take four naked men down an alley and then heard gunshots. The observers said the soldiers informed them the prisoners were IS fighters.
As the observers were leaving the area, one of them told Human Rights bodies of a number of naked men were seen lying in a doorway.
IS lost control of the Old City after nine months of fighting with Iraqi forces who are supported by a U.S.-led coalition. Fighting in the area continued for several days after Prime Minister Haider al-Abadi declared victory over IS on July 10. Videos were distributed showing Iraqi troops beating unarmed men and killing one by pushing him off a cliff.
Iraq has vowed to investigate earlier allegations of abuses and to take appropriate action against those responsible.
Iraqi government spokespeople have not responded to these latest allegations.