Ukrainian prosecutors have launched an investigation into an alleged Russian execution of a Ukrainian soldier found dead with a sword inscribed with “for Kursk” in his body, in an apparent act of revenge for Kyiv’s recent incursion into the Russian border region.

In a photo circulating online, a man is seen lying on his back on a rubble-strewn road with a medieval-style sword protruding from his chest. Duct tape can be seen around the wrists of one of his blood-stained arms.

The words “for Kursk” are written in Cyrillic on the sword, in seeming reference to Ukraine’s cross-border attack on the Kursk region, the first foreign invasion of Russian territory since World War II.

Ukraine’s prosecutor general, Andriy Kostin, said on Tuesday that the image showed “another act of barbarism” by Russia. His office later confirmed it had opened a criminal investigation into the alleged execution.

“Footage of an alleged execution by sword of an unarmed Ukrainian serviceman with taped hands is spreading on the web,” he wrote on X. “Russia continues its deliberate policy of eliminating everything Ukrainian, demonstrating worldwide its brutal cruelty and cynically disregarding any values and norms of the civilized world.”

Kostin said preliminary assessments showed the incident occurred in Novohrodivka, a city in Ukraine’s eastern Donetsk region.

Ukraine’s human rights commissioner, Dmytro Lubinets, said the alleged execution was “a violation of the Geneva Convention on the Treatment of Prisoners of War.” Under this convention, prisoners of war must not be subjected to torture and must be protected from violence.

Kyiv is investigating nearly 130,000 war crimes allegedly committed by Moscow since Russia launched its full-scale invasion in February 2022, Kostin said in June.

Thursday’s image comes as Russia is stepping up its efforts to expel Ukrainian forces from Kursk. Ukrainian President Volodymyr Zelensky acknowledged the start of Russia’s counteroffensive and said the Kremlin intends to deploy up to 70,000 troops to the region, but said last week that Moscow’s forces “have not yet had any serious success.”

Meanwhile, Russia is inching forward toward Pokrovsk, northwest of Novohrodivka, where the alleged sword execution occurred.

In an update Thursday, Ukraine’s military said its troops had thwarted 40 Russian attacks near Pokrovsk over the past 24 hours, and that the attacks were most fierce near Hrodivka and Novohrodivka.

The Kremlin has not commented on the alleged execution.

This post appeared first on cnn.com