Russian President Vladimir Putin vowed to crush what he called an armed mutiny by mercenary boss Yevgeny Prigozhin, warning those who have taken up arms against the Russian military will face "inevitable punishment".
In Russia's first armed insurrection since the Chechen wars 20 years ago, heavily armed fighters from Prigozhin's Wagner militia were in control of the streets of Rostov-on-Don, a city of more than a million people close to the border with Ukraine.
In televised address, Putin said he would do everything to protect Russia, and that "decisive action" would be taken to stabilise the situation in Rostov-on-Don.
Putin described the actions of the mutineers as a "stab in the back".
“All those who prepared the rebellion will suffer inevitable punishment. The armed forces and other government agencies have received the necessary orders,” he said.
Putin said "excessive ambitions and vested interests" had led to "treason".
"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 urged “those who are being dragged into this crime not to make a fatal and tragic, unique mistake, to make the only right choice - to stop participating in criminal acts.”
Putin went on to condemn the rebellion at a time when Russia was “fighting the toughest battle for its future” with its war in Ukraine.
“The entire military, economic and information machine of the West is waged against us,” he said.
“This battle, when the fate of our people is being decided, requires the unification of all forces, unity, consolidation and responsibility.”
Russia's defence ministry said Wagner fighters were "tricked into the criminal adventure and armed rebellion" by Prigozhin.
In a statement carried on state-run media, the ministry said many Wagner members "had already realised their mistake" and now wanted assistance from the authorities to be able to "return safely" to their permanent bases.
Authorities in Moscow and the surrounding area declared a counterterrorism state of emergency against the background of the armed uprising.
"In order to prevent possible terrorist attacks in the city and Moscow region, a regime of counterterrorism operations has been established," Russia's National Antiterrorism Committee announced on Saturday morning.
Security has been tightened in Moscow. The Voronezh region in south-western Russia, which borders Ukraine, also declared this type of state of emergency.
The counterterrorism state of emergency allows the Russian authorities to increase controls and facilitate the arrest of citizens. Telephone calls can also be tapped more frequently. However, it was initially unclear what concrete measures were to be taken in Moscow and Voronezh.
Earlier on Saturday, Moscow Mayor Sergei Sobyanin had already announced "anti-terror measures." In the Russian capital, a city of more than 13 million citizens, increased traffic checks had already been introduced on the streets. During the night, military vehicles were also on the road in the city centre.
with agencies