Mutinous Russian mercenaries who surged most of the way to Moscow have agreed to turn back to avoid bloodshed, their leader said on Saturday, in a de-escalation of what had become a major challenge to President Vladimir Putin’s grip on power.

The fighters of the Wagner private army were just 200 kilometres from the capital, said the leader, former Putin ally Yevgeny Prigozhin. The rebels had captured the city of Rostov hundreds of miles to the south before racing across the country.

“They wanted to disband the Wagner military company. We embarked on a march of justice on June 23. In 24 hours we got to within 200km of Moscow. In this time we did not spill a single drop of our fighters’ blood,” Prigozhin said in an audio message.

“Now the moment has come when blood could be spilled. Understanding … that Russian blood will be spilled on one side, we are turning our columns around and going back to field camps as planned.”

The decision to halt further movement across Russia by the Wagner group was brokered by Belarusian President Alexander Lukashenko in return for guarantees for their safety, his office said. There was no immediate word on the deal from Putin.

Earlier, Prigozhin said his men were on a “march for justice” to remove corrupt and incompetent Russian commanders he blames for botching the war in Ukraine.

In a televised address from the Kremlin, Putin said Russia’s very existence was under threat.

Facing the first serious challenge to his grip on power of his 23-year rule, President Vladimir Putin vowed to crush an armed mutiny he compared to Russia’s Civil War a century ago.

The dramatic turn, with many details unclear, looked like the biggest domestic crisis Putin has faced since he ordered a full-scale invasion of Ukraine — something he called a “special military operation” — in February last year.

“We are fighting for the lives and security of our people, for our sovereignty and independence, for the right to remain Russia, a state with a thousand-year history,” he said.

Putin said that “excessive ambitions and vested interests have led to treason”, and called the mutiny a “stab in the back”.

“This is a stab in a back to our country, to our nation,” Putin said to the nation. “What we have been faced with is exactly betrayal.

“It is a blow to Russia, to our people. And our actions to defend the Fatherland against such a threat will be harsh.

“All those who deliberately stepped on the path of betrayal, who prepared an armed insurrection, who took the path of blackmail and terrorist methods, will suffer inevitable punishment, will answer both to the law and to our people.”

He acknowledged a “difficult” situation was unfolding in the southern city of Rostov-on-Don, where the Wagner mercenary group has taken control of key military sites in an effort to oust the Russian military’s top brass.

“There will be decisive measures taken on stabilising the situation in Rostov-on-Don,” Putin said in an address to Russians. “It remains difficult and the work of civil and military authorities in fact is being blocked.”

A defiant Prigozhin swiftly replied that he and his men had no intention of turning themselves in.

“The president makes a deep mistake when he talks about treason. We are patriots of our motherland, we fought and are fighting for it,” Prigozhin said in an audio message. “We don’t want the country to continue to live in corruption, deceit and bureaucracy.”

Prigozhin, whose private army fought the bloodiest battles in Ukraine even as he feuded for months with the top brass, said he had captured the headquarters of Russia’s Southern Military District in Rostov without firing a shot.

Reuters saw troop carriers and a flatbed truck carrying a tank careening past the city of Voronezh more than halfway to Moscow, where a helicopter fired on them. But there were no reports of the rebels meeting any substantial resistance on the highway.

Russian media showed pictures of small groups of police manning machine gun positions on Moscow’s southern outskirts Authorities in the Lipetsk region south of the capital told residents to stay home.

More than 100 firefighters were in action at a fuel depot ablaze in Voronezh. Video footage obtained by Reuters showed it blowing up in a fireball shortly after a helicopter flew by. Prigozhin accused Russia’s military of hitting civilian targets from the air as it tried to slow the column’s advance.

In Rostov, which serves as the main rear logistical hub for Russia’s entire invasion force, residents milled about calmly, filming on mobile phones as Wagner fighters in armoured vehicles and battle tanks took up positions.

One tank was wedged between stucco buildings with posters advertising the circus. Another had “Siberia” daubed in red paint across the front, a clear statement of intent to sweep across the breadth of Russia.

In Moscow, there was an increased security presence on the streets. Red Square was blocked off by metal barriers.

In a series of hectic messages overnight, Prigozhin demanded that Defence Minister Sergei Shoigu and the chief of the general staff Valery Gerasimov should come to see him in Rostov.

Western capitals said they were closely following the situation in nuclear-armed Russia. The White House said President Joe Biden was briefed.

“This represents the most significant challenge to the Russian state in recent times,” Britain’s defence ministry said.

“Over the coming hours, the loyalty of Russia’s security forces, and especially the Russian National Guard, will be key to how this crisis plays out.”

Putin’s grip on power may depend on whether he can muster enough loyal troops to combat the mercenaries at a time when most of Russia’s military is deployed at the front in southern and eastern Ukraine.

The insurrection also risks leaving Russia’s invasion force in Ukraine in disarray, just as Kyiv is launching its strongest counteroffensive since the war began in February last year.

“Russia’s weakness is obvious. Full-scale weakness,” Ukrainian President Volodymyr Zelenskiy wrote in a social media message. “And the longer Russia keeps its troops and mercenaries on our land, the more chaos, pain and problems it will have for itself later.”

Prigozhin’s revolt

Prigozhin, a former convict and long-time ally of Putin, leads a private army that includes thousands of former prisoners recruited from Russian jails.

His men took on the fiercest fighting of the 16-month Ukraine war, including the protracted battle for the eastern city of Bakhmut.

He railed for months against the regular army’s top brass, accusing generals of incompetence and of withholding ammunition from his fighters. This month, he defied orders to sign a contract placing his troops under Defence Ministry command.

He launched the apparent mutiny on Friday after alleging that the military had killed many of his fighters in an air strike. The Defence Ministry denied it.

“There are 25,000 of us and we are going to figure out why chaos is happening in the country,” he said, promising to destroy any checkpoints or air forces that got in Wagner’s way. He later said his men had been involved in clashes with regular soldiers and had shot down a helicopter.

Army Lieutenant-General Vladimir Alekseyev issued a video appeal asking Prigozhin to reconsider.

“Only the president has the right to appoint the top leadership of the armed forces, and you are trying to encroach on his authority,” he said.

Russia’s FSB security had earlier opened a criminal case against Prigozhin for armed mutiny and had said that his statements were “calls for the start of an armed civil conflict on Russian territory and his actions a ‘stab in the back’ of Russian servicemen fighting pro-fascist Ukrainian forces”.

It added: “We urge the … fighters not to make irreparable mistakes, to stop any forcible actions against the Russian people, not to carry out the criminal and traitorous orders of Prigozhin, to take measures to detain him.”

The state news agency TASS quoted Kremlin spokesman Dmitry Peskov as saying that all of Russia’s main security services were reporting to Putin “round the clock”.

Security was being tightened in Moscow, Mayor Sergei Sobyanin said on his Telegram channel.

On Friday, Prigozhin had appeared to cross a new line in his increasingly vitriolic feud with the ministry, saying that Putin’s stated rationale for invading Ukraine 16 months ago was based on lies concocted by the army’s top brass.

“The war was needed … so that Shoigu could become a marshal … so that he could get a second ‘Hero’ [of Russia] medal,” Prigozhin said in a video clip.

“The war wasn’t needed to demilitarise or denazify Ukraine,” he said, referring to Putin’s justifications for the war.

At about 2am (11pm GMT), Prigozhin posted a message on the Telegram app saying his forces were in Rostov and ready to “go all the way” against the top brass and destroy anyone who stood in their way.

At about 5am (2am GMT), the administration of the Voronezh region, on the M-4 motorway between the regional capital Rostov-on-Don and Moscow, said on Telegram that a military convoy was on the highway and urged residents to avoid using it.

Unverified footage posted on social media showed a convoy of assorted military vehicles, including at least one tank and one armoured vehicle on flatbed trucks.

It was not clear where they were, or whether the covered trucks in the convoy contained fighters. Some of the vehicles were flying the Russian flag.

Footage on channels based in Rostov-on-Don showed armed men in military uniform skirting the regional police headquarters in the city on foot, as well as tanks positioned outside the headquarters of the Southern Military District.

Reuters confirmed the locations shown but could not determine when the footage was shot.

UK says Russia facing greatest challenge of recent times

Separately, Britain’s defence ministry said on Saturday that the Russian state was facing its greatest security challenge of recent times, following what it said appeared to be a move by Wagner Group forces towards Moscow.

“Over the coming hours, the loyalty of Russia’s security forces, and especially the Russian National Guard, will be key to how this crisis plays out. This represents the most significant challenge to the Russian state in recent times,” Britain’s defence ministry said in a regular intelligence update.

Military Convoy

Prigozhin denied that he was trying to stage a military coup.

He said he had led his fighters out of Ukraine to Rostov, where a video posted by a pro-Wagner Telegram channel showed him, seemingly relaxed, conversing with two generals at the headquarters of Russia’s huge Southern Military District.

The video showed him telling the generals: “We have arrived here, we want to receive the chief of the general staff and Shoigu. Unless they come, we’ll be here, we’ll blockade the city of Rostov and head for Moscow.”

That appeared to be a reference to a military convoy trying to make a 1,200-km drive towards Moscow, ostensibly to topple the military leadership.

Russian local officials said a military convoy was indeed on the main motorway linking the southern part of European Russia with Moscow, and warned residents to avoid it.

Army General Sergei Surovikin, the deputy commander of Russian forces in Ukraine, whom Prigozhin has praised in the past, said in a video that “the enemy is just waiting for our internal political situation to deteriorate”.

“Before it is too late … you must submit to the will and order of the people’s president of the Russian Federation. Stop the columns and return them to their permanent bases,” he said.

An unverified video on a Telegram channel close to Wagner showed the purported scene of an air strike against Wagner forces.

It showed a forest where small fires were burning and trees appeared to have been broken by force. There appeared to be one body, but no more direct evidence of any attack.

It carried the caption: “A missile attack was launched on the camps of PMC (Private Military Company) Wagner. Many victims. According to eyewitnesses, the strike was delivered from the rear, that is, it was delivered by the military of the Russian Ministry of Defence.”

Russia’s anti-terrorist committee said it was imposing a counter-terrorist regime in Moscow and the surrounding region amid an apparent mutiny by the Wagner mercenary group, RIA reported.

Russia’s Defence Ministry said in a statement addressed to Wagner Group mercenary fighters that they had been “deceived and dragged into a criminal adventure” by Wagner chief Yevgeny Prigozhin.

In a statement posted on Telegram, the ministry urged Wagner fighters to contact its representatives and those of law enforcement services, and promised to guarantee their security.

Three killed in latest Russian air strike on Ukraine

Meanwhile, at least three people were killed early on Saturday after Russia unleashed its latest overnight air strike on Ukraine, officials said.

Ukrainian Interior Minister Ihor Klymenko said missiles had targeted at least five regions across the country and that three people were killed and eight wounded after a high-rise in the capital Kyiv was struck.

“This is the style of terrorists. The style of Russia,” he wrote on the Telegram messaging app.

In a separate post, Serhiy Popko, head of Kyiv’s military administration, said the damage had been caused by fragments from a downed missile and that air defences had shot down more than 20 missiles around the city.

Emergency workers on Saturday morning were sifting through debris at the scene, where a gaping hole was visible on one side of the building.

Officials in the southeastern region of Dnipropetrovsk said eight people were wounded — two of them children — and several buildings were destroyed in attacks there.

Governor Serhiy Lysak said air defences had destroyed nine missiles and three drones but that residential buildings in the regional capital Dnipro and an unspecified infrastructure object were hit.

“Not a single military target,” Mayor Borys Filatov wrote separately on Telegram.

At least three Russian missiles also targeted Kharkiv, Ukraine’s second-largest city, with one hitting a gas line and triggering a fire, said Mayor Ihor Terekhov. He said emergency services were at the scene but gave no details on casualties.

There were reports of explosions in other cities but no indication of casualties or damage.

Moscow began stepping up regular air strikes on Ukraine in May as Kyiv’s military was planning a counteroffensive, which is now ongoing, to retake Russian-occupied territory in the east and south.