- One video circulating online appears to show Russians beheading a Ukrainian serviceman with a knife.
- Ukrainian President Volodymyr Zelenskyy said it was "the execution of a Ukrainian captive."
Ukraine accused Russia of executing its servicemen after videos purporting to show the beheading of Ukrainian soldiers began circulating online.
Ukrainian President Volodymyr Zelenskyy on Wednesday responded to one of the videos, saying that it showed "the execution of a Ukrainian captive."
"There is something that no one in the world can ignore: how easily these beasts kill," Zelenskyy said, adding that Russia is trying to make "destroying life" into the "new norm."
The video, which has not been verified, shows what appears to be a Russian soldier using a knife to behead a man wearing Ukrainian military clothing.
Given the amount of foliage on the ground, it was likely filmed during the summer, CNN reported.
Dmytro Kuleba, Ukraine's foreign minister, described it as a "horrific video of Russian troops decapitating a Ukrainian prisoner of war."
Kuleba accused Russia of being "worse than ISIS" and said that "Russian terrorists must be kicked out of Ukraine and the UN and be held accountable for their crimes."
The Islamic State previously released videos of it beheading captives.
Another video shared by a pro-Russia Telegram channel last week also appeared to show Ukrainian soldiers lying dead with their heads cut off, CNN reported.
While the video was purportedly filmed by Russian mercenaries from the Wagner group, according to CNN, Wagner founder Yevgeny Prigozhin denied the claim on his company's Telegram account.
"I watched this video. It's bad when people's heads are cut off, but I haven't found anywhere that this is happening near Bakhmut and that Wagner PMC fighters are participating in the execution," he said.
Russia has not commented on the videos, but has previously denied that any of its servicemen have committed atrocities or war crimes in Ukraine.
Seemingly responding to the first video, Zelenskyy said the apparent killing was "not an accident" but instead part of a pattern by Russia, pointing to alleged war crimes in the town of Bucha.
When Russia pulled back from the Kyiv suburb last year, investigators found bodies with their hands tied behind backs and gunshot wounds to their heads.
Investigators said that there was evidence to show that Russian forces "carried out targeted, organized killings of civilians in Bucha."
Dariia Zarivna, an adviser to the Head of the Office of the President of Ukraine, said on Telegram on Wednesday that the videos were "aimed at intimidation" and showed "the essence of a terrorist country," according to CNN's translation.
"The target audience is not only Ukraine, but also Western societies," she added. "It doesn't work on us, though. The Russians are afraid of this, but not us."
Ukraine's Security Service announced on Wednesday that it was opening a pre-trial war crimes investigation.
"We will find these non-humans. We will get them wherever they are: from underground or from the other world if necessary. But they will be punished for what they have done," Security Service chief Vasyl Maliuk said, according to a translation by Ukrainian media outlet Rubryka.