Lynne Tracy, the U.S. ambassador to Moscow, met with detained American journalist Evan Gershkovich on Monday, the ambassador's press secretary told ABC News.

Tracy met with Wall Street Journal reporter at Moscow's Lefortovo prison where he's being held, according to the press secretary.

This is the second visit between Tracy and Gershkovich since his initial detention in March.

-ABC News' Tanya Stukalova and Ellie Kaufman

Yevgeny Prigozhin, the Wagner Group leader who led the rebellion in Russia, reportedly released a new message Monday, his first in a week, to a social media account with ties to the PMC.

In a short audio message posted by Grey Zone telegram account, which believed to be run by a Wagner member that frequently posts about events on the frontline in Ukraine, Prigozhin claimed the June 24 rebellion against Moscow was aimed at "fighting traitors and mobilizing our society."

"I think we have achieved a lot of it. In the near future, I am sure that you will see our next victories at the front. Thanks guys," he allegedly said.

The Wagner Group leader said "today, more an ever, we need your support."

-ABC News' Patrick Reevell

Amid fears Russia might blow up the Zaporizhzhia nuclear power plant, Ukraine is holding drills to prepare emergency services with how to deal with a potential radioactive disaster.

ABC News was invited to the drills in the city of Zaporizhzhia this week, about 30 miles from the plant, where firefighters in hazmat gear simulated decontaminating people from radiation during an evacuation.

Emergency workers demonstrated scanning civilians with Geiger counters as they disembarked buses, stripping some civilians and hosing them with water as they lay on stretchers. Firefighters in yellow suits sprayed down vehicles and moved them through a large washer system rigged up between fire trucks.

This week, Ukraine's chief of military intelligence, Kyrylo Budanov, claimed Russia had now completed preparation to potentially sabotage the plant if it chooses.

Read more about the drills here.

-ABC News' Patrick Reevell

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New concern about Ukraine nuclear plant

Ukraine President Volodymyr Zelenskyy has accused Russia of planning to trigger an explosion at Zaporizhzhia, Europe’s largest nuclear plant.

CIA Director Bill Burns said Yevgeny Prigozhin's mutiny showed the "corrosive effect" of President Vladimir Putin's war in Ukraine during remarks in England on Saturday.

"It is striking that Prigozhin preceded his actions with a scathing indictment of the Kremlin’s mendacious rationale for its invasion of Ukraine, and of the Russian military leadership’s conduct of the war," Burns said during a lecture to Britain's Ditchley Foundation. "The impact of those words and those actions will play out for some time, a vivid reminder of the corrosive effect of Putin’s war on his own society and his own regime."

Burns, who served as U.S. ambassador to Russia from 2005 to 2008, also noted how Russian disaffection will gnaw away at the Kremlin and that the CIA is taking this opportunity to step up its recruitment efforts in Russia.

"Disaffection with the war will continue to gnaw away at the Russian leadership, beneath the steady diet of state propaganda and practiced repression," Burns said. "That disaffection creates a once-in-a generation opportunity for us at CIA, at our core a human intelligence service. We're not letting it go to waste."

-ABC News' Cindy Smith