The simmering conflict between the leadership in Moscow and Wagner's boss, Yevgeny Prigozhin, has dramatically escalated into open rebellion that plunges Russia into uncertainty and has brought back shadows of the bloody civil war of 1917.
Prigozhin after Rostov claims that during the early hours of Saturday he also took control of the main military facilities in the city of Voronezh, located about 310 miles from Moscow, already targeting the capital.
Prigozhin said in a video that he is in Rostov-on-Don, in southern Russia, near the border with Ukraine, and that his forces are in control of military facilities and the airport there.
He vowed to blockade Rostov and go to Moscow unless Russia's defense minister and top general meet with him in the city, which is home to Russia's Southern Military District.
Rostov-on-Don is a strategic point because its military headquarters coordinates operations in Ukraine, a former British military intelligence officer has said.
Prigozhin's move comes after he said his fighters were entering the Rostov region on Friday and that Russian Guards and military police have joined the Wagner group, but CNN could not independently verify his claims.
So the photos and videos circulating on social media, mainly on Telegram, show Wagner's troops taking complete control of Rostov, with heavily armed soldiers and armored tanks surrounding the main buildings.

Pictures show military vehicles on the road and in the early morning there were reports of helicopters hovering over the city.
The Wagner Group later said it had taken control of Russian military facilities in the southwestern Russian city of Voronezh, saying "the army is going over to the side of the people". Earlier, the governor of the Voronezh region said that "a convoy of military equipment is moving along the federal highway M-4", which connects Voronezh and Rostov-on-Don.
Prigozhin, on the other hand, also claimed that a helicopter shot down a civilian convoy and was shot down by his forces, but gave no further details. He accused the Russian army chief of staff of ordering an airstrike "among civilian cars". Later, he said his units were hit by a helicopter on a highway.
Prigozhin accuses Russia of killing his soldiers and is calling the rebellion a "march of justice" rather than a coup as claimed by the Kremlin, while saying all 25,000 of his soldiers are ready to die for the Russian people.
"We continue, we will reach the end. We will destroy anyone who stands in our way. We are all about to die, all 25,000 of us. And then there will be another 25,000. Because we will die for the motherland, we will die for the Russian people, who must be freed from those who bomb the civilian population," Prigozhin threatened in the audio message on Telegram.
Russia's Defense Ministry denied Prigozhin's claims, calling it an "informational provocation", while accusing Prigozhin of "armed rebellion".
The Federal Security Service (FSB) responded by asking Wagner's fighters to arrest their leader and on Friday opened a criminal case against Prigozhin, accusing the head of the mercenary force of calling for "armed rebellion", the state news agency reported. TASS news.
Meanwhile, Vladimir Putin responded to his former ally, reminding him that what he is doing is treason and that he is stabbing Russia in the back.
"It is an attempt to overthrow us from within. This is treason," Putin said.
"We are fighting against anarchy and capitulation. This internal uprising is a death blow for us," Putin said in his address to the nation, adding that countermeasures will be very difficult.
"This is an adventurous criminal campaign. It is tantamount to armed rebellion. Russia will defend itself. Security measures have been taken in Moscow and other regions. The situation around Rostov remains very complicated. I am doing everything to repel this attack. Those who started the uprising have betrayed Russia and I call on everyone involved in it to stop any kind of participation in the armed conflict", he further stated.