Dmytro Lubinets based his accusation on information from the Deep State open-source intelligence project, which cited its sources as the 1st Separate Tank Brigade.

Lubinets wrote on the Telegram messaging app on Sunday that Russia has “systematically executed” Ukrainian POWs throughout the war and that such violations of international law have been confirmed independently, including by the UN.

“Multiple reports indicate that Russian forces have systematically executed Ukrainian POWs during the ongoing war, violating international laws like the Geneva Convention,” Lubinets wrote on October 10 along with a pixelated picture of the dead soldiers. “Both Ukrainian and international sources, including the United Nations, confirm these violations. The Kremlin denies involvement in any war crimes.”

Lubinets said he had sent a letter to the UN and ICRC about “another crime by the Russians,” believed to have been committed on October 9, stressing that the perpetrators should be held to account.

“Russia is a terrorist country that violates all the rules and customs of war," Lubinets wrote in his Telegram post. “The international community should not turn a blind eye to such crimes.”

Commenting on the reports, Ukraine's foreign minister, Andrii Sybiha, called for the international community to intervene.

“Russia's mistreatment of Ukrainian prisoners of war is absolute barbarism, grave violation of international humanitarian law, laws and customs of war,” Ukrainska Pravda news website quoted him as saying. “Executions are becoming more frequent; 95% of POWs are subjected to torture according to the UN, denied basic needs and access.

“[The] international community must take immediate action,” he continued. “Issue ICC arrest warrants for Russian executioners and torturers. Boost sanctions pressure. Demand access for international monitors and medics to detention sites, facilitate release of POWs and all illegally detained persons."