President Vladimir Putin vowed Saturday to defend Russia against an armed rebellion by mercenary chief Yevgeny Prigozhin, who led his troops out of Ukraine and into a key city south of Moscow. 

Meanwhile, the governor of Russia's Lipetsk province said Saturday that Prigozhin's Wagner mercenary group has entered the region, which is about 360 kilometers (225 miles) south of Moscow, where authorities "are taking all necessary measures to ensure the safety of the population," said regional Gov. Igor Artamonov, via Telegram. 

Moscow on Saturday erected checkpoints with armored vehicles and troops on its southern edge, Red Square was shut down and the mayor urged motorists to stay off some roads as the Russian capital braced for the arrival of a private army led by a rebellious mercenary commander.

The uprising, which Putin called "a stab in the back," was the biggest threat to his leadership in over two decades in power.

The private army led by Prigozhin appears to control the military headquarters in Rostov-on-Don, a city 660 miles (over 1,000 kilometers) south of Moscow that runs Russian offensive operations in Ukraine, Britain's Ministry of Defense said in an intelligence briefing.

In his address, Putin called the uprising by Prigozhin, whom he did not mention by name, a "betrayal" and "treason."

"All those who prepared the rebellion will suffer inevitable punishment," Putin said. "The armed forces and other government agencies have received the necessary orders."

Prigozhin called himself a patriot and said his fighters would not surrender, as "we do not want the country to live on in corruption, deceit and bureaucracy."

"Regarding the betrayal of the motherland, the president was deeply mistaken. We are patriots of our homeland," he said in an audio message on his Telegram channel.

He said his fighters would not turn themselves in at the request of Putin, as "we do not want the country to live on in corruption, deceit and bureaucracy."

Prigozhin's Wagner, a private mercenary army, has been fighting alongside Russian troops in Ukraine. It wasn't immediately clear what his aims were, but the rebellion marks an escalation in Prigozhin's struggle with Russian military leaders, who he has accused of botching the war in Ukraine and hamstringing his forces in the field.

"This is not a military coup, but a march of justice," Prigozhin said.

Prigozhin confirmed Saturday he and his troops reached Rostov-on-Don after crossing the border from Ukraine. Photos from the Reuters news agency and videos posted on social media showed Wagner's troops, tanks and other military vehicles in the streets of the city. 

Prigozhin posted a video of himself at the Russian military headquarters in Rostov and claimed that his forces had taken control of the air field and other military facilities in the city. According to CBS News correspondent Ian Lee, there are reports that Wagner troops have seized a second city halfway to Moscow, but he did not specify which city that was.  

Prigozhin said his forces faced no resistance from young conscripts as they crossed into Russia, saying his troops "aren't fighting against children."

"But we will destroy anyone who stands in our way," he said in one of a series of angry video and audio recordings posted on social media beginning late Friday. "We are moving forward and will go until the end."

• What is the Wagner group, and who is Yevgeny Prigozhin? What to know about the Russian private military company

Putin condemned the rebellion, which comes at a time when Russia is "fighting the toughest battle for its future" as western governments heap sanctions on Moscow and arm Ukraine.

"The entire military, economic and information machine of the West is waged against us," Putin said.

Russia's security services called for Prigozhin's arrest after he declared an armed rebellion late Friday. The Kremlin also tightened security at key facilities around the country overnight.  Moscow woke up to a state of emergency, and Putin has ordered anti-terror measures in several regions, giving law enforcement broad legal powers.

It was not immediately clear how Prigozhin was able to enter the southern Russian city or how many troops he had with him.

Prigozhin said his aim was to punish Defense Minister Sergei Shoigu after Russian government forces attacked Wagner field camps in Ukraine with rockets, helicopter gunships and artillery.

Gen. Valery Gerasimov, chief of the General Staff, ordered the attacks following a meeting with Shoigu at which they decided to destroy Wagner, Prigozhin said. He said Wagner's forces shot down a Russian military helicopter that fired on a civilian convoy, but there was no independent confirmation.

Prigozhin said he had 25,000 troops under his command and urged the army not to offer resistance.

The 62-year-old Prigozhin, a former convict, has long ties to the Russian leader and won lucrative Kremlin contracts that earned him the nickname "Putin's chef."

He gained attention in the U.S. when he and a dozen other Russian nationals and three Russian companies were charged with operating a covert social media campaign aimed at fomenting discord ahead of Donald Trump's 2016 presidential election victory. He formed the Wagner mercenary group, which sent military contractors to Libya, Syria, several African countries and eventually Ukraine.

After Putin's address, in which the Russian leader didn't mention concrete steps to suppress the rebellion but rather called for unity in the face of the revolt, officials and state media personalities in the country sought to publicly reiterate their allegiance to the Kremlin and urged Prigozhin to back down.

Vyacheslav Volodin, speaker of Russia's lower house of parliament, the State Duma, said that the Duma lawmakers "stand for the consolidation of forces" and support Putin, adding that "Wagner fighters must make the only right choice: to be with their people, on the side of the law, to protect the security and future of the Motherland, to follow the orders of the Commander-in-Chief."

Foreign Ministry spokeswoman Maria Zakharova echoed Volodin's sentiment and said in a Telegram post that "we have one commander in chief. Not two, not three. One."

Ramzan Kadyrov, the strongman leader of the Chechnya region who used to side with Prigozhin in his criticism of the military leadership, also expressed his full support of "every word of" Putin.

"We have the commander in chief, elected by the people, who knows the situation to the slightest detail better than any strategist and businessman," Kadyrov said. "The mutiny needs to be suppressed."

While the outcome of the confrontation was still unclear, it appeared likely to further hinder Moscow's war effort as Kyiv's forces were probing Russian defenses in the initial stages of a counteroffensive. The dispute, especially if Prigozhin were to prevail, also could have repercussions for Putin and his ability to maintain a united front.

The Wagner forces have played a crucial role in Ukraine, succeeding in taking the eastern city of Bakhmut, where the bloodiest and longest battles have taken place. But Prigozhin has increasingly criticized Russia's military brass, accusing it of incompetence and of starving his troops of weapons and ammunition.

Heavy military trucks and armored vehicles were seen in several parts of central Moscow early Saturday, and soldiers toting assault rifles were deployed outside the main building of the Defense Ministry. The area around the presidential administration near Red Square was blocked, snarling traffic.

But even with the heightened military presence, downtown bars and restaurants were filled with customers. At one club near the headquarters of the FSB, people were dancing in the street near the entrance.

Prigozhin, whose feud with the Defense Ministry dates back years, had refused to comply with a requirement that military contractors sign contracts with the ministry before July 1. In a statement Friday, he said he was ready to find a compromise but "they have treacherously cheated us."

"Today they carried out a rocket strike on our rear camps, and a huge number of our comrades got killed," Prigozhin said. The Defense Ministry denied attacking the Wagner camps.

"The evil embodied by the country's military leadership must be stopped," he shouted.

Col. Gen. Sergei Surovikin, the deputy commander of the Russian group of forces fighting in Ukraine, urged the Wagner forces to stop any move against the army, saying it would play into the hands of Russia's enemies, who are "waiting to see the exacerbation of our domestic political situation."

In Washington, the Institute for the Study of War said "the violent overthrow of Putin loyalists like Shoigu and Gerasimov would cause irreparable damage to the stability of Putin's perceived hold on power."

At the White House, National Security Council spokesperson Adam Hodge said: "We are monitoring the situation and will be consulting with allies and partners on these developments."

In:
• Ukraine
• Politics
• Russia
• Vladimir Putin
• Moscow