KYIV, April 12 - Ukraine launched an investigation Wednesday into a gruesome video that purportedly shows the beheading of a Ukrainian soldier, in the latest accusation of atrocities said to have been committed by Russia since it invaded in February 2022.

The video spread quickly online and drew outrage from officials in Kyiv, including President Volodymyr Zelenskyy, as well as international organizations, The Associated Press reported. The Kremlin called the footage “horrible” but said it needed to be verified.

Meanwhile, a Russian defense official claimed that fighters from Russia’s paramilitary Wagner group have seized three districts of Bakhmut, the embattled city that for months has been the focus of Moscow’s grinding campaign in the east.

The video circulating online appears to show a man in green fatigues wearing a yellow armband, typically donned by Ukrainian fighters. His screams are heard before another man in camouflage uses a knife to decapitate him.

A third man holds up a flak jacket apparently belonging to the man being beheaded. All three men speak in Russian.

Since Russia’s forces invaded on Feb. 24, 2022, they have committed widespread abuses and alleged war crimes, according to the United Nations, rights groups and reporting by The Associated Press. Ukraine has repeatedly accused Russia of targeting apartment buildings and other civilian structures and equipment in its strikes, and images of hundreds of dead civilians in the streets and in mass graves in Bucha after Russian forces withdrew from the city have horrified the world.

The International Criminal Court has issued an arrest warrant for Russian President Vladimir Putin for war crimes, accusing him of personal responsibility for the abductions of children from Ukraine.

The Kremlin denies it has committed war crimes or that it has targeted civilians.

Ukrainian troops have also been accused of abuses, and last year Kyiv said it would investigate video circulating online that Moscow alleged showed Ukrainian forces killing Russian troops who may have been trying to surrender.

Zelenksyy said the violence in the latest video would not be forgotten, and that Russian forces would be held responsible.

“Everyone must react, every leader. Do not expect that it will be forgotten, that time will pass,” he said in a video.

In it, he used strong language to describe Russian soldiers, calling them “beasts.”

Later Wednesday, at a roundtable of IMF and World Bank meetings, Zelenskyy called in a video for a moment of silence for the Ukrainian soldier killed in the apparent beheading.

Kremlin spokesman Dmitry Peskov said the video was “horrible” but must be verified.

“In the world of fakes we live in, the authenticity of the footage must be checked,” he said in a conference call with reporters.

Ukraine’s state security service opened an investigation, according to a statement from Vasyl Maliuk, the head of the agency, known as the SBU. Officials are studying the video to identify those responsible, as well as the victim, according to Hanna Maliar, the deputy head of the Defense Ministry.

Posters on pro-Kremlin Russian Telegram channels, while not confirming the video’s authenticity, did not dispute it. Some sought to justify it by saying combat has hardened Russian troops. (ap/ez)