Ukraine’s human rights commissioner urged the International Committee of the Red Cross (ICRC) and the United Nations to investigate an image widely shared online on Saturday that he said likely showed a Ukrainian prisoner-of-war killed and dismembered by Russian forces.

Ukraine’s prosecutor general said separately that an urgent investigation had been launched into information being spread on social networks about the murder and dismemberment of a Ukrainian POW.

“A photograph, probably of a Ukrainian prisoner whose head and limbs were cut off by the Russians, has appeared online,” Dmytro Lubinets, the country’s leading human rights official, said in a post on the Telegram messaging app.

“In view of these horrific images, I have urgently appealed to the ICRC and the UN to record yet another human rights violation by the terrorist country,” Lubinets wrote.