The Security Service of Ukraine (SBU) says it has launched an investigation into the online appearance of a video on social media purporting to show the beheading of a Ukrainian prisoner of war.
The SBU announced the probe on April 12 as Ukrainian President Volodymyr Zelenskiy blasted Russian forces as "beasts" over the video of the alleged decapitation. It has not been independently verified.
The Kremlin called the video "horrible," but added that its authenticity needed to be studied as "we live in a world of fakes."
"There is something that no one in the world can ignore: how easily these beasts kill.... We won't forget anything, nor will we forgive murderers," Zelensky said in a video message posted on Twitter on April 12.
Amid growing outrage over the video, Ukrainian Deputy Defense Minister Hanna Malyar said officials were studying the video to identify those responsible, as well as the victim.
The SBU said the investigation would try to determine whether there had been a violation of the rules of war that say “prisoners of war must at all times be humanely treated.”
"We will find these inhumane.... They will definitely be punished for what they did," the head of the SBU, Vasyl Malyuk, was quoted as saying.
Earlier, Andriy Yermak, a top adviser to Zelenskiy, said on Telegram that there “will be an accountability for everything.”
According to CNN, a video posted on social media on April 8 appeared to show the beheading of corpses of two Ukrainian soldiers lying next to a destroyed military vehicle. The video was purportedly filmed by members of the private Russian mercenary group Wagner.
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Reports on Russian social media claimed the video was shot near the eastern city of Bakhmut, which has been devastated by weeks of heavy fighting.
Another video posted on social media on April 11 appeared to show Russian forces torturing a Ukrainian prisoner and cutting off his head. RFE/RL could not independently verify the footage.
Speaking to reporters in Moscow, Kremlin spokesman Dmitry Peskov said, "This is terrible footage, and first you need to check the authenticity. If it is confirmed, then we need to find where and by whom," the action was committed.
Ukrainian Foreign Minister Dmytro Kuleba said it was "absurd" that Russia currently holds the rotating presidency of the UN Security Council while "Russian terrorists" have invaded Ukraine.
The UN Human Rights Monitoring Mission in Ukraine said it was "appalled" by the “particularly gruesome videos.”
Dmytro Lubinets, Ukraine’s human rights chief, said he will request that the UN Human Rights Committee investigate. Lubinets said he also has written to the UN Commissioner for Human Rights, the UN Monitoring Mission in Ukraine, UN Secretary-General Antonio Guterres, and the International Committee of the Red Cross.
“A public execution of a captive is yet another indication of a breach of Geneva Convention norms, international humanitarian law, a breach of the fundamental right to life,” Lubinets said.
For its part, the EU said it remains committed to holding war criminals accountable.
“We don't have more information on the veracity of the video. Having said that, if confirmed, this is yet another brutal reminder about the inhumane nature of the Russian aggression," EU spokeswoman Nabila Massrali said.
Since its troops invaded Ukraine in February 2022, Russia has been accused of committing various war crimes, accusations it denies.
Last month, the United Nations expressed deep concern over what it says were summary executions of prisoners of war by both Russian and Ukrainian forces on the battlefield.
Earlier in April, the UN Human Rights Council overwhelmingly voted in favor of extending and expanding the mandate of an investigative body probing possible war crimes in Ukraine.
The Geneva Convention, the international law regarding the treatment of prisoners of war, says “any unlawful act or omission by the Detaining Power causing death or seriously endangering the health of a prisoner of war in its custody is prohibited, and will be regarded as a serious breach of the present Convention.”