The Freedom of Russia Legion is the other group that claims to have been involved, and also portrays itself as Russians who are fighting for Ukraine and against Putin.
The legion says on its website that it was formed last spring “out of the wish of the Russians themselves to fight against Putin’s armed gang in the ranks of the Armed Forces of Ukraine.”
The group calls on Russian soldiers and officers to join them in the fight for “Free Russia.”
It claims to be officially recognized by Ukraine’s army, and fighting “under the leadership of the Ukrainian command” in many places, including in Bakhmut.
The group was banned as a terrorist organization by Russia’s Supreme Court in March.
No particular names of leaders or people affiliated with the Legion are shared on the group’s site. But a man nicknamed “Caesar” has appeared in videos on the group’s channel as its de facto spokesperson.
“We are Russians, just like you,” he said in a video on the Legion’s Telegram channel on Monday ahead of the raid in Belgorod, as he decried corruption and Putin’s crackdown of civil liberties. “We are coming home,” he said.
The Legion said in March that Russia started a criminal case against “Caesar,” without identifying his real name.
And state news agency Tass reported Wednesday that officials were looking for a man named Maximillian Andronnikov, who it identified as a member of an ultranationalist organization. It said he was suspected of being part of the Legion’s group that penetrated into Belgorod.
The Legion also has a strong presence on Telegram, where they call themselves “free citizens of Russia,” with more than a quarter million subscribers.
Earlier this month, RVC vowed to fight in tandem with the Legion “despite a different ideological base.” It’s not clear how many fighters there are in either group.
“The Russian Volunteer Corps does seem especially heavily drawn from Russian nationalists and neo-Nazis, while the Legion appears less politically-aligned,” Mark Galeotti, who heads the Russia-focused consultancy Mayak Intelligence, told NBC News.
“They share a desire to see the Putin regime fall and believe a Ukrainian victory is the best way to further this goal,” Galeotti said.
What’s their motivation?
Kapustin, the commander of the RVC, told the press near the Russian border Wednesday that his group makes no secret of some of its members’ right-wing views, but he doesn’t think that being called a neo-Nazi is an insult.
“You will never find me waving a flag with a swastika, you will never find me, I don’t know, raising my hand in a Hitler salute,” he said.
Sporting a goatee and all-black military fatigues, Kapustin touted the success of the Belgorod raid and said a wider operation was being planned.
The group says that it fully recognizes Ukraine’s territorial integrity and considers Putin’s war in Ukraine “criminal.” It lists the “overthrow of the ruling regime in Russia” as one of its objectives.
Meanwhile, Alexei Baranovsky, the spokesperson for the political wing of the Legion told Reuters the incursion was “the first steps in the main objective of overthrowing Putin’s regime through armed force.”
In a post on the group’s Telegram channel on Wednesday the Legion vowed to return soon. “Belgorod, Bryansk, Kursk, Voronezh, Rostov, Moscow — wait for us,” the post said.
The group’s manifesto calls Putin’s regime “dictatorial,” and says they are fighting against him and “for true freedom for every Russian.” It also calls on both ethnic Russians and minorities in the country to rise against the Russian leader.
“It’s clear that Freedom of Russia Legion and Russian Volunteer Corps are both predominantly Russian groups — self-styled ‘partisans’ trying to bring the Putin government down and that they range from the soccer-thug neo-Nazis to the wannabe celebrities and even to some semi-serious political reformers,” said Michael Clarke, visiting professor of war studies at King’s College London.
“They are not ‘liberals’, but rather hard line Russian nationalists — just not of the Putin variety,” Clarke added.
NBC News has reached out for comment to both groups, but they did not immediately respond.
What’s their connection to Ukraine?
The Kremlin does not dispute that some of the fighters involved in the incursion this week could be ethnically Russian, but sees them as “Ukrainian militants, coming from Ukraine,” according to spokesman Dmitry Peskov.
Ukraine has denied it’s connected to actions by either group, framing them as “Russian patriots” who decided to rise up against the Kremlin.
The groups’ extreme views and evidence that the fighters involved in this week’s raid appeared to use American armored vehicles has raised questions for Washington, which has sought to ensure that equipment sent to Kyiv is not used in attacks on Russian soil. The Kremlin has baselessly sought to frame its war as a fight against a government of neo-Nazi Western puppets.
Andriy Yusov, a spokesman for Ukraine’s military intelligence directorate, told NBC News the incursion was carried out “exclusively by citizens of the Russian Federation” who had acted “completely autonomously” and that Ukraine did not coordinate with them.
Kyiv has consistently denied responsibility for drone attacks, train derailments and other incidents that have fueled unease within Russia, frequently painting them as the work of partisans.
But Kapustin, the RVC commander, said Ukraine “encouraged” the group’s actions in Belgorod, and that they “consult” on their actions with Ukraine’s military, though he said anything they do outside the country’s borders “is our own decision.”
Baranovsky, of the Legion, said the unit was part of Ukraine’s international brigade, but denied the incursion was coordinated with Ukrainian authorities.
Experts also questioned Kyiv’s narrative that it was a purely Russian affair.
“There’s no question really that the Russian volunteer units are armed and controlled by Ukraine, specifically GUR, military intelligence,” Galeotti said.
“Although it suits Kyiv to pretend that this was simply a venture by Russian patriots, it would only have been carried out by GUR’s orders, or at least with its approval,” he added, referring to the intelligence branch of Ukraine’s defense ministry.