Russia-Ukraine updates: Russian missile strikes hit multiple Ukrainian cities
Dozens of injuries were reported in Kyiv and other Ukrainian cities.
Russia has continued a nearly 19-month-long invasion of neighboring Ukraine. Recently, though, the Ukrainians have gone on a counteroffensive, fighting to reclaim occupied territory.
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Uprising 'significant challenge' to Russian state, UK says
Members of the mercenary Wagner Group have begun moving north "almost certainly aiming to get to Moscow," in what amounts to the "most significant challenge to the Russian state in recent times," the U.K. Ministry of Defense said on Saturday.
"Over the coming hours, the loyalty of Russia's security forces, and especially the Russian National Guard, will be key to how the crisis plays out," the ministry said on Twitter.
Putin: Wagner Group moves are 'stab in the back'
Russian President Vladimir Putin said moves taken by Wagner Group leader Yevgeny Prigozhin, a longtime ally, to bring his troops into a key Russian city amounted to a "stab in the back."
Putin didn't mention Prigozhin by name, but said that "necessary orders have been given" to defend Russia in a recorded address aired on Russian television on Saturday.
"Actions that divide our unity are in essence defeatism before one's own people," he said. "This is a stab in the back of our country and our people."
-ABC News' KJ Edelman
Kremlin briefs Putin on 'attempted armed rebellion'
Russian President Vladimir Putin has been briefed by the country's security agencies about what was referred to as an "attempted armed rebellion," according to Russia's state-run media.
The late-night statement from Putin's spokesman suggested that the Kremlin considered Wagner Group's move into Rostov-on-Don, a key Russian city close to the border with Ukraine, to be a "rebellion."
Wagner's founder Yevgeny Prigozhin in an audio message on Friday claimed his forces would now punish Russia's defense minister and chief of general staff, telling other units to stand down and not offer resistance.
"Special services, law enforcement agencies, namely the Ministry of Defense, the FSB, the Ministry of Internal Affairs, Rosgvardiya, in round-the-clock mode, constantly report to the president on the measures taken in the context of the implementation of the instructions previously given to him," Kremlin spokesperson Dmitry Peskov said on Saturday.
-ABC News' Tanya Stukalova and Patrick Reevell
What is the Wagner Group?
The Wagner Group is a private military organization run by Yevgeny Prigozhin, a longtime ally of Russian leader Vladimir Putin, with tens of thousands of fighters, according to U.S. officials.
Earlier this year, the U.S. labeled the group a "significant transnational criminal organization" and levied new sanctions, while human rights observers this week said they suspected Wagner fighters were linked to the mass killing of people in Mali last year.
Government reports, statements from U.S. officials and insights from experts, as well as other sources, shed light on the Wagner group's history and goals, its alleged wrongdoings and its importance to Russia -- in Ukraine and elsewhere in the world.
-ABC News’ Nathan Luna, Leah Vredenbregt and Ivan Pereira
Kremlin denies role in plane crash believed to have killed Prigozhin
Russia on Friday vehemently denied having any involvement in the mysterious plane crash that is believed to have killed Wagner Group leader Yevgeny Prigozhin.
"There has been a lot of speculation around this crash [and] the tragic deaths of the plane's passengers, among them Yevgeny Prigozhin. Of course, the West presents all this speculation from a particular angle. All of that is sheer lies," Kremlin spokesperson Dmitry Peskov told reporters while answering questions during a press briefing. "One should rely on facts. For now, there are not many facts, they have yet to be established in the ongoing investigative procedures."
Prigozhin, 62, was a former close ally of Russian President Vladimir Putin. His private paramilitary organization played a key role in Putin's invasion of neighboring Ukraine before briefly launching an insurrection against the Russian military in June. Forces loyal to Prigozhin marched toward Moscow before turning back after several days.
A private jet was en route from Moscow to St. Petersburg on Wednesday when it went down near the village of Kuzhenkino in Russia's Tver region, north of Moscow. All 10 people on board were killed. Prigozhin and Wagner Group co-founder Dmitry Utkin were among the passengers identified on a flight list, according to Russian officials.
The U.S. Department of Defense said Thursday that Prigozhin was "likely" killed in the plane crash.