The Iraqi government has said it will investigate a graphic video that appears to show its soldiers killing an unarmed suspected Islamic State fighter by throwing him off a high ledge.

The video was reportedly filmed in the Mosul area where Iraqi troops have largely retaken a city once controlled by the extremist group, and comes amid mounting concern over claims of abuse committed by Iraqi soldiers and police in the battle for Mosul and in its aftermath.

Commenting on the video, an Iraqi interior ministry spokesman said if the footage was authentic, those responsible must be brought to justice.

The video was first posted online by the Mosul Eye blog on Wednesday, two days after Iraq’s prime minister, Haider al-Abadi, formally declared victory over Isis in the city.

The footage shows a man being held in a building and then dragged by soldiers across an open area to a ledge above a drop of at least 30ft where another body lies motionless.

It appeared alongside a second video that has also been circulating on social media which appears to show a man in Iraqi army fatigues gunning down an unarmed man kneeling in front of a car.

Commenting on the videos, Human Rights Watch Iraq researcher Belkis Wille said on Thursday: “These horrific reports of mistreatment and murder have been met by silence from Baghdad, only further fostering the feeling of impunity among armed forces in Mosul.”

The video emerged as HRiW also raised concerns over Iraq’s establishment of a tent camp near Mosul which authorities describe as a “rehabilitation camp” for Isis suspects’ families.

The camp is located in Bartella, around 12 miles (20km) east of Mosul, and houses at least 170 families, mostly women and children from areas of western Mosul, where the last battles against Isis took place before the city was declared liberated this week, the New York-based group said.

The camp was opened on Sunday, after a directive from Mosul’s district council that said “so-called Isis families should be sent to receive psychological and ideological rehabilitation”, HRW added.

Citing interviews with some families, HRW said they were brought against their will because of accusations that they had relatives linked to Isis.

“Iraqi authorities shouldn’t punish entire families because of their relatives’ actions,” said Lama Fakih, deputy director of the Middle East and North Africa division at HRW. “These abusive acts are war crimes and are sabotaging efforts to promote reconciliation in areas retaken from Isis,” she added.

HRW said the camp had a mobile medical clinic, but only very limited humanitarian services, with no schools, training, or other programmes.

At least 10 women and children died at, or traveling to, the camp, most of them because of dehydration, HRW added, citing medical workers at the site.