The government of Russia confirmed late Friday that it had opened an investigation into and filed charges against the leader of the Wagner paramilitary group, Yevgeny Prigozhin, for calling for “armed rebellion” against Moscow.

Prior to the announcement by the Federal Security Service, Prigozhin published several video messages on Friday claiming that Russian Defense Minister Sergey Shoigu ordered an attack on Wagner positions in Ukraine and killed “a large number of our fighters.” He later reportedly claimed through social media videos that he had turned his forces around and entered Rostov-on-Don, Russia, allegedly with little resistance. The city is home to important military installments and the Wagner chief reportedly claimed Shoigu was present there.

Prigozhin, whose troops are at the forefront of the ongoing “special operation” by Russian leader Vladimir Putin to oust Ukrainian President Volodymyr Zelensky, had become increasingly vocal against the Ukrainian invasion and Shoigu, in particular, in the past few months, though he had limited criticism of Putin directly and claimed to maintain close relations to the strongman.

Multiple reports translating Prigozhin’s online messages claim that he vowed to bring his troops, which he claimed to number up to 25,000 men, into Moscow, but insisted, “this is not a military coup.”

Reports out of Moscow indicate that the Russian government has begun to fortify the capital. In Rostov, regional Gov. Vasily Golubev published a message on Telegram telling civilians to “keep calm and not leave home without need,” according to the Russian state outlet RT. Reports circulating throughout Telegram, Twitter, and other social media outlets indicated the potential presence of Wagner fighters in the Rostov region generally, but most alleged video or photo evidence was undated and unverified.

The ongoing crisis began on Friday with the publication of a video in which Prigozhin accused Shoigu, the defense minister, of ordering an attack on his positions in Ukraine that allegedly killed 2,000 Wagner militants.

“Those who destroyed our lads, who destroyed the lives of many tens of thousands of Russian soldiers, will be punished. I ask that no one offer resistance,” Prigozhin reportedly said, according to a translation by NBC News. Wagner-affiliated accounts on Telegram reportedly circulated unverified videos claiming to show the aftermath of a Russian missile attack on Wagner.

A separate translation by the Associated Press similarly noted that Prigozhin had vowed to march into Moscow with 25,000 fighters but insisted, “This is not a military coup, but a march of justice.”

Prigozhin claimed in a subsequent message to already be in Rostov, alleging that Russian forces had not attempted to prevent the Wagner contingent’s passage.

The Russian government called allegations of an alleged Russian attack on Wagner “entirely unfounded.”

In another message, Prigozhin condemned the Ukrainian invasion itself as a ploy by senior leaders in the Russian Defense Ministry to appear competent and heroic.

“The war was needed … so that [Defense Minister Sergei] Shoigu could become a marshal … so that he could get a second ‘Hero’ [of Russia] medal,” Prigozhin reportedly said, according to NBC News. “The war wasn’t needed to demilitarize or denazify Ukraine.”

RT acknowledged online videos circulating allegedly showing “an armed confrontation between Wagner PMC forces and the Russian Army,” but did not verify those reports. It also claimed the situation in Rostov, despite warnings from local officials for civilians to stay indoors, was “relatively calm.”

Videos circulating on social media, allegedly from Ukrainian sources, appeared to show military movement in Rostov. According to the Azerbaijani network Kanal13, the videos showing military movement in Rostov were from Ukrainian Telegram channels; the network did not independently verify the authenticity or the date of the videos, or whether they were taken in Rostov. Breitbart News similarly could not independently verify the authenticity of the social media footage.

In Moscow, the government reportedly deployed a significant security presence, though the city remained quiet in the early hours of Saturday local time, according to the independent Moscow Times.

“A Moscow Times reporter in central Moscow did not see a significant military or police presence near the Kremlin,” the newspaper reported. “Elsewhere in the capital, columns of military vehicles were filmed near the Defense Ministry headquarters and the road leading to the presidential administration building was reportedly closed off.”

Video surfacing online allegedly of Moscow on Friday night into Saturday morning showed military vehicles on the streets, as reported by Voice of America.

“All the most important facilities, state authorities and transport infrastructure facilities have been taken under enhanced protection,” the Times quoted the Russian news agency Tass as reporting.

The AP and Tass also reported an increased security presence, but no active hostilities, in Moscow and Rostov as of early Saturday morning local time. Tass noted that government roadblocks had appeared around Rostov, presumably to block any potential Wagner invasion.

Putin has not made any public statements at press time, but the Kremlin claimed he had been briefed and was monitoring the situation. The Russian government also confirmed that Prigozhin would face charges for calling for an armed insurrection.

“Amid the seriousness of the situation and the threat of escalation of confrontation in the Russian Federation the FSB has opened a criminal case into the fact of a call for an armed rebellion on the part of Yevgeny Prigozhin,” the Federal Security Agency’s (FSB) Public Relations Center announced on Saturday, according to Tass.

The FSB described the various Prigozhin statements as “calls for the state of an armed civil conflict on Russian territory” and “a stab in the back” for Russian troops in Ukraine. He faces between 12 and 20 years in prison.

Prigozhin had already been criticizing the Russian leadership, and Shoigu in particular, for their allegedly poor performance in Ukraine — so much so that he felt compelled to claim he was not planning a coup d’etat against Putin in late May. He nonetheless launched into a familiar tirade about Shoigu at the time, who he claimed was more likely to oust Putin than he was.

“As a citizen, I am deeply indignant that these scum sit quietly and sit on their fat assholes smeared with expensive creams,” Prigozhin said at the time.

A week prior to that message, Prigozhin expressed concern that what he perceived as incompetence on the part of the Russian Defense Ministry could result in a revolution against Putin.

“We are in such a condition that we could fucking lose Russia – that is the main problem … We need to impose martial law,” he reportedly said. “First the soldiers will stand up, and after that – their loved ones will rise up. There are already tens of thousands of them – relatives of those killed. And there will probably be hundreds of thousands – we cannot avoid that.”

“This divide can end as in 1917 with a revolution,” he warned.

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