Updated June 24, 2023 at 6:23 AM ET

Russian President Vladimir Putin condemned an uprising by the head of a pro-Kremlin mercenary force against his Defense Ministry as a "stab in the back" that risked undermining Russia's war effort in Ukraine.

"Those who organized this military uprising, who raised arms against their fellow military comrades will answer for it," Putin said in an address to the nation Saturday morning.

The Kremlin leader called on those participating in the rebellion to "make the only right choice: Stop taking part in this criminal activity."

While mentioning no names, Putin's address appeared squarely aimed at Wagner mercenary chief Yevgeny Prigozhin, who was formally charged with "inciting an armed revolt" by Russia's Federal Security Bureau early Saturday.

The criminal charge came as Prigozhin — in a remarkable series of posts to social media — accused the Russian military's top brass of carrying out lethal attacks on his soldiers and vowed to remove the Defense Minister Sergei Shoigu by force.

Prigozhin also claims his soldiers now control several military installations in Rostov-on-Don, a key southern Russian city that serves as a logistical base for the war effort in Ukraine.

In response, authorities have introduced "anti-terrorism operations" in the capital, Moscow, and in Rostov-on-Don to restore order.

Russia's Defense Ministry says Wagner forces are marching on Moscow.

In an audio message on his Telegram channel, Prigozhin later said Putin is "deeply mistaken" about who is the traitor to the country and that neither he nor his fighters are about to surrender on the orders of the president, the FSB or anyone else.

Wagner forces, who number between 20,000-50,000, had been fighting alongside the regular Russian army in Ukraine, and claimed credit for taking the Ukrainian town of Bakhmut after months of bitter fighting. Those actions have been accompanied though by Prigozhin's near constant criticism of the Russian military's top brass' means and tactics.

Ukraine watches turmoil in Russia

In Ukraine, President Volodymyr Zelenskyy posted a statement on his Telegram channel, saying, "Russia's weakness is obvious. A full-scale weakness. And the longer Russia keeps its troops and mercenaries on our land, the more chaos, pain and problems it will create for itself."

"Ukraine is able to protect Europe from the spread of Russian evil," he added.

The head of Ukraine's military intelligence, Kyrylo Budanov, also addressed the internal tensions in Russia, saying, "This is a very real conflict. Why is this striking? Because Prigozhin, whether you like it or not, is basically telling the truth, while the (Russian) Defense Ministry is mostly telling lies."

Russian military officials, Budanov added, are saying, " 'Everything is fine there, we are winning, there are some young brave soldiers somewhere.' On the contrary, Prigozhin says, 'Look around you. This is definitely not a victorious war. We cannot win here. Look at the miscalculations, there is nothing to shoot with. I don't know what to do with the army, they are not trained.' "

No immediate impact on the fighting in Ukraine

Russia launched a heavy overnight barrage of missiles, firing more than 40 at cities around Ukraine.

The primary target was Kyiv, where air raid sirens wailed and explosions rang out through the night as Russia directed more than 20 missiles at the capital city and surrounding areas.

Ukraine's military said it shot down all the missiles aimed at Kyiv, which is often the case in such attacks.

However, falling debris hit a high-rise apartment building, igniting a fire and causing casualties. Three people were killed and more than 10 were injured, Kyiv officials said.

As events were rapidly unfolding in Russia, it was too early to tell how it might effect the war in Ukraine.

However, Oleksiy Danilov, the head of Ukraine's National Security and Defense Council, predicted the internal Russian quarreling would ultimately lead to Russian troops leaving Ukraine.

"The Ukrainian formula for sustainable peace foresees the exit to the borders of 1991 and the launch of the processes of Russia's self-destruction," he said on Twitter. "As the war began, so it will end — inside the Russian Federation."

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