The short but very unpleasant video has been widely circulated on Telegram and Twitter.
In the clip, a man in a Ukrainian uniform is seen lying on the ground. He is unarmed and thus a prisoner of war. Over him sits a man wearing what appears to be a Russian uniform. A few seconds into the clip, the man in Russian uniform sits on the prisoner of war and beheads him. He then turns to the cameraman and holds his head up.
Execution, torture or ill-treatment of prisoners of war is a violation of humanitarian law and Ukrainian authorities have opened an investigation into suspected war crimes.
"Don't think that case in oblivion"
The clip appears to have been filmed during the summer months and has not been verified. The soldiers who captured the killed man are wearing white armbands on their legs, a characteristic used by Russian soldiers during the war.
In Ukraine, the images have sparked outrage. Foreign Minister Dimitry Kuleba says it is "worse than ISIS" and Volodymyr Zelenskyy calls the Russian soldiers "beasts".
"Don't think it will be forgotten," the Ukrainian president said.
Left: The slain man wears a Ukrainian emblem and a yellow blindfold on his leg. Right: The soldiers in the clip are wearing white armbands, which have been used as hallmarks for Russian soldiers in the war.
Kremlin: Horrible images
The Kremlin has also commented on the images, with spokesman Dimitry Peskov calling them "horrible". At the same time, he says that the authenticity of the clip must be established. There may also be reason to investigate when and where the clip was recorded and who appears in the clip, Peskov adds.