Kyiv on Tuesday accused Russian forces of beheading a Ukrainian serviceman in the eastern Donetsk region, the latest allegation of abuse levied by Ukrainian prosecutors against Moscow.
Both Ukraine and Russia have accused each other's militaries of battlefield misconduct tantamount to war crimes, and Kyiv has called for a special tribunal to investigate abuses as part of conditions to end the war.
"While conducting aerial reconnaissance at one of the combat positions in the Donetsk region, the Ukrainian military discovered a damaged armoured vehicle of the Ukrainian Defence Forces. It contained the severed head of a Ukrainian defender," the office of Ukraine's prosecutor general posted on social media.
Prosecutor General Andriy Kostin claimed that Russian forces operating in the Volnovakha district were ordered to take no Ukrainian soldiers as prisoners of war and instead "kill them with inhuman cruelty -- by beheading".
His office posted a picture purporting to show the armoured military vehicle with a section blurred, indicating where the alleged severed head was observed by Ukrainian drones.
There was no immediate response to the claims from Moscow and AFP was unable to independently verify the allegations put forward by the Ukrainian prosecutors.
Kostin was quoted as saying that the incident would not go unpunished and that he also called on "the entire civilised world to isolate and punish the terrorist country," referring to Russia.
The prosecutor general's office said it had opened an investigation into violations of the laws and customs of war, and pre-meditated murder.