Russian state-run media said fighters from the resistance groups, the Free Russia Legion and the Russian Volunteer Corps, were largely defeated in Belgorod on Tuesday.
Around 70 militants were killed after Russia’s armed forces, Federal Security Service and border patrol agents cracked down on the resistance forces with the assistance of air strikes and artillery fire.
The revolutionary fighters had marched into Belgorod on Monday and claimed the liberation of two towns, Kozinka and Gora-Podol, before moving into Grayvoron.
After Russia invaded Ukraine last year, Belgorod has come under frequent bombardments. Until this week, however, the region bordering Ukraine has never seen a large contingent of pro-Ukrainian troops move into local towns.
Mark Hertling, a retired former commanding general of the U.S. Army in Europe, said he believed the incursion was a strategic raid designed to distract, spook and send a message to the Kremlin.
“There may be other such raids/feints/demonstrations to gather more information about Russian force dispositions and reinforcement priorities,” Hertling predicted on Twitter.
Several Russian civilians have been injured in Belgorod and at least one person died during an evacuation, according to the regional governor, Vyacheslav Gladkov.
Gladkov said at least 100 civilians were evacuated from towns and areas but later on Tuesday said residents were slowly returning to their homes and crucial services like electricity were being restored.
Both the Free Russia Legion and the Russian Volunteer Corps were formed last year, made up of defecting Russians who wished to defend Ukraine.
In social media posts and videos posted online, the Free Russia Legion said they were revolting against widespread corruption under Russian President Vladimir Putin and seeking to overthrow his regime.
Ukrainian officials have denied any involvement in the resistance groups in Belgorod, though they have welcomed their efforts.
