The Russian Volunteer Corps, one of the Russian anti-government groups who have declared themselves to be fighting on Ukraine's side, said its members had once again entered Russia's territory on May 25.
The anti-Kremlin fighters recorded a video saying they "are back in the Motherland" with what appears to be a Russian Post brunch in the background.
The building seen in the video has a sign saying Glotovo, the name of a village in Russia's Belgorod region. Glotovo is located some five kilometers from the Russo-Ukrainian border.
The Kyiv Independent could not independently verify the group's claim or the footage published on its Telegram channel.
"Once again, we enter the territory of Russia with battles or quietly — it doesn't matter anymore," the armed men in the video said. "The flame of struggle is burning all over the country. Wait for us in your town."
On May 22, a group of armed men calling themselves the Free Russia Legion and the Russian Volunteer Corps claimed they had crossed into Russia's Belgorod region and taken hold of bordering villages.
The Russian Defense Ministry said they had defeated what they called "Ukrainian formations," claiming to have "killed 70 combatants" and destroyed four armored combat vehicles and five trucks while "driving the remaining formations from Belgorod Oblast back into Ukrainian territory."
However, the Russian Volunteer Corps denied these claims. The Ukrainian official, who spoke anonymously, told the New York Times that the armed groups had suffered losses, but not enough to affect their fighting capacity.
The Russian Volunteer Corps previously claimed to have conducted attacks on Bryansk Oblast on March 4, claiming the Ukrainian military's support. Kyiv has denied any connection to the group's operations.