May 22 (Reuters) - The governor of Russia's Belgorod region said on Monday that a Ukrainian 'sabotage group' had entered Russian territory in the Graivoron district, which borders Ukraine, and was being repelled by Russian forces.
However, the Ukrainian outlet Hromadske cited Ukrainian military intelligence as saying two armed Russian opposition groups, the Liberty of Russia Legion and the Russian Volunteer Corps (RVC), both consisting of Russian citizens, had carried out the attack.
The Telegram channel Baza, which has links to Russia's security services, published aerial footage apparently showing a Ukrainian armoured vehicle advancing on the Graivoron border checkpoint.
Kremlin spokesman Dmitry Peskov said Russian President Vladimir Putin had been informed, and that work was under way to drive out the "saboteurs", the state-run RIA Novosti news agency reported.
Belgorod governor Vyacheslav Gladkov said on Telegram that the Russian army, border guards, presidential guards and the FSB security service were involved in the operation. He said no civilians had been harmed, and that there was no evacuation under way.
Baza said there were indications of fighting in three settlements along the main road leading into Russia. The "Open Belgorod" Telegram channel said power and water had been cut off to several villages.
Reuters was unable to verify the reports and the Ukrainian military was not immediately available for comment.
A group calling itself the Liberty of Russia Legion - a Ukraine-based Russian militia led by Russian opposition figure Ilya Ponomarev that says it is working inside Russia for Putin's overthrow, said on Twitter it had "completely liberated" the border town of Kozinka. It said forward units had reached the district centre of Graivoron, further east.
"Moving on. Russia will be free!" it wrote.
The group also released a video showing five heavily armed fighters.
"We are Russians, like you. We are people like you. We want our children to grow up in peace," one said, facing the camera. "It is time to put an end to the dictatorship of the Kremlin."
Hromadske quoted Ukrainian military intelligence spokesperson Andriy Yusov as saying the Belgorod operation would create a "security zone" to protect Ukrainians from cross-border attacks by Russia.
The Kremlin said the aim of the incursion was to distract attention from the eastern Ukrainian town of Bakhmut, which Russian forces claim finally to have captured in its entirety after more than nine months of attritional fighting.
"We understand perfectly well the goal of such a diversion - to divert attention from the Bakhmut direction and minimise the political effect of Bakhmut's loss for the Ukrainian side," Peskov was quoted as saying.
Early in March, the FSB reported an incursion from Ukraine by an "armed group of Ukrainian nationalists" into Russia's Bryansk region.
In videos circulating online at the time, armed men saying they belonged to the RVC described themselves as Russian "liberators", and said they had crossed the border to fight what they referred to as "the bloody Putinite and Kremlin regime".
The RVC was founded last August by Denis Kapustin, a Ukraine-based Russian nationalist, and announced on May 17 on its Telegram channel that it was joining forces with the Freedom of Russia Legion.
The RVC has fought on various fronts of the Ukraine war alongside Ukrainian forces and says it has made at least three incursions into the Bryansk region since March.
