Iraq has opened an inquiry into claims that its forces abused and killed civilians in the battle for Mosul against so-called Islamic State (IS).

An interior ministry statement said it would take legal measures against anyone proven to have been “negligent”.

It comes after Der Spiegel published an article by a photojournalist who was embedded with the ministry’s troops.

Ali Arkady says he took pictures of detainees suspended from ceilings and that others were tortured and raped.

The unit in question says the report is “fabricated”.

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In the article in this week’s issue of Der Spiegel, a German magazine, Arkady says he had set out last year wanting to bring attention to the “heroes” of the interior ministry’s Emergency Response Division (ERD). However, he adds, he ended up documenting their “war crimes”.

Arkady, who has left Iraq with his family over fears for their safety, says he became close to two members of the ERD and that they allowed him to witness and photograph abuses allegedly committed by their unit over several months.

He says they allowed him to take pictures – published by Der Spiegel – of men suspected of links to IS being hanged from the ceiling by their arms, of a man being stabbed behind the ear, and of a woman threatened with rape.

Arkady alleges he was told by troops that men he saw being detained had been “tortured to death” and that a male Sunni pro-government tribal fighter was raped by Shia ERD personnel.

A statement issued by the ERD accused Der Spiegel of publishing a report based on “fabricated and unreal images”, according to Reuters news agency.

The US envoy to the multinational coalition against IS, which is supporting the ERD and other units on the ground in Iraq, wrote on Twitter: “Iraqi forces have bravely placed civilian protection as top priority throughout #Mosul campaign, at great risk to their own personnel.”

But he added: “Individuals or units failing to uphold that standard do a disservice to their sacrifice and must be investigated & held accountable.”