President Biden said Thursday he has no idea where Russian mercenary chief Yevgeny Prigozhin is, but joked that the Wagner chief should watch what he eats wherever he is. 

"If I were he, I'd be careful what I ate," Biden told reporters at a press conference in Helsinki. "I'd be keeping my eye on my menu." 

The president's remarks came in response to a reporter's question on whether disarray among Russian generals could precipitate more drastic action from Russian President Vladimir Putin, such as using nuclear weapons or further interference in U.S. elections. 

Putin, head of the Russian state since 1999, has said the Wagner Group's aborted mutiny against senior Russian military commanders risked civil war and compared it to the revolutionary turmoil of 1917. However, despite this heated rhetoric, he has permitted Prigozhin to live after the June 24 mutiny and not prosecuted any of the Wagner Group's forces. 

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President Joe Biden speaks at the presidential palace in Helsinki, Finland

President Biden said there is no "real prospect" of Russian President Vladimir Putin using nuclear weapons. (Andrew Caballero-Reynolds/AFP via Getty Images)

Prigozhin, a fierce critic of how Russian military leaders have waged war in Ukraine, had reportedly gone into exile in Belarus after his purported rebellion. Since the events of that day, neither Prigozhin nor General Sergei Surovikin, a deputy commander of Russia's military operations in Ukraine, have been seen in public. 

Surovikin's disappearance fueled speculation that Putin was executing a purge of commanders deemed insufficiently loyal or hesitant in their response to the mutiny. Pentagon press secretary Brig. Gen. Pat Ryder said last month that the Defense Department had not received intelligence "that would portend strategic instability." 

Since then, Russian Maj. Gen. Ivan Popov was reportedly fired for criticizing top military brass. 

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A split image shows Belarusian President Alexander Lukashenko, Wagner Group leader Yevgeny Prigozhin, and Russian President Vladimir Putin

From left, Belarusian President Alexander Lukashenko, Wagner Group leader Yevgeny Prigozhin and Russian President Vladimir Putin. (Natalia Kolesnikova/AFP via Getty Images | Stringer/Anadolu Agency via Getty Images | Contributor/Getty Images)

"The Ukrainian army could not break through our ranks at the front but our senior chief hit us from the rear, viciously beheading the army at the most difficult and intense moment," Popov said in a voice message published by Russian lawmaker Andrei Gurulyov. 

Popov explicitly raised the deaths of Russian soldiers from Ukrainian artillery and said the army lacked proper counter artillery systems and reconnaissance of enemy artillery, Reuters reported.

Reports of his subsequent dismissal prompted a reporter to ask Biden whether Putin is about to take "drastic" action amid the apparent instability.

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US President Joe Biden and Finland's President Sauli Niinisto

President Biden and Finland President Sauli Niinisto attend a joint press conference after the U.S.-Nordic leaders' summit in Helsinki on July 13, 2023. (Andrew Caballero-Reynolds/AFP via Getty Images)

"I don't think there's any real prospect — you never know — of Putin using nuclear weapons," Biden said. "Not only has the West, but China and the rest of the world have said that's … don't go there." 

As to Prigozhin's ultimate fate, Biden said it was anyone's guess. 

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"Who knows?" he said. "I don't know. I don't think any of us know for certain what the future of Prigozhin is in Russia. And so I don't know how to answer that question beyond that." 

Reuters contributed to this report.