Vyacheslav Gladkov, governor of Russia's Belgorod Oblast, announced a "counter-terrorist operation" in the region on May 22 amid reported attacks by Russian anti-government groups.
During such operation, the Russian authorities can increase ID checks and law enforcement presence on the streets, force locals to leave certain areas, and shut down industrial facilities that use explosive, radioactive, chemically, and biologically dangerous substances.
Earlier the same day, the Russian Volunteer Corps, allegedly fighting on Ukraine's side, claimed its members conducted combat operations in the Belgorod region bordering Ukraine.
A similar group, the Freedom of Russia Legion, said it was "returning home" to Russia and urged Russian citizens not to resist their arrival. Later, the group reported capturing the settlements of Kozinka and Gora-Podol and starting an assault on Grayvoron town in the Belgorod region.
According to Gladkov, three people were purportedly injured in Grayvoron as a result of what he called an attack by a Ukrainian sabotage-reconnaissance group. He previously claimed two people had been wounded in a strike on a village near Grayvoron.
The Kyiv Independent is unable to independently verify these claims.
The Kremlin's spokesperson Dmitry Peskov said, as cited by Russian state-owned news agency TASS that Russia's dictator Vladimir Putin had already been informed of the incident. Peskov added that Russian forces were working to "push out" the "sabotage group" from the region.
Andrii Yusov, a spokesperson for Ukraine's military intelligence, confirmed the operation to Ukrainian news outlet Suspilne, saying it aims "to liberate these territories from Putin's regime and push back the enemy to create a certain security zone for protecting Ukrainian civilians."
Yusov then told CNN that the units that had crossed the border were "part of defense and security forces" in Ukraine, but "in Russia, they are acting as independent entities."
The Ukrainian leadership has "nothing to do" with May 22 events in Belgorod Oblast, according to Mykhailo Podoliak, an advisor to the head of Ukraine's Presidential Office.