Russia-Ukraine updates: Russian missile strikes hit multiple Ukrainian cities

Ukrainian Armed Forces have yet to reach their "full potential," but two top generals exclusively told ABC News the counteroffensive is "going to plan" despite concerns from Western analysts that Ukraine is not making enough progress.

Gen. Oleksandr Tarnavskyi, who is leading the counteroffensive in the south, told ABC News' chief global affairs correspondent Martha Raddatz that the situation is "stable."

"The main thing is that we haven’t reached our full potential," Tarnavskiy said.

Ukrainian troops launched the counteroffensive a month ago, attacking on multiple axes on the southern frontline in Zaporizhzia using Western-supplied vehicles. Ukraine succeeded in piercing Russian lines at two points, liberating a string of villages, but has since been locked in ferocious fighting

Gen. Oleksandr Syrskyi, commander of the Ukrainian ground forces, told Raddatz that last month's failed rebellion by the Putin-backed PMC, the Wagner Group, wouldn't impact the fighting on the ground.

"It would be better for us if there were some negative consequences in Russia itself, but it doesn't matter for me," he said.

Asked if he was confident of retaking the key city of Bakhmut, Syrskyi said, "Yes, of course. I’m sure."

Both sides have suffered heavy casualties, according to Western officials, particularly in the south where Russia has so far conducted "relatively effective defensive operations" in the southeastern Zaporizhzhia province, the U.K. Ministry of Defense reported.

"The enemy is suffering eight times or even 10 times higher losses, especially with the number of killed troops," Syrksyi said.

-ABC News' Guy Davies and Meghan Mistry

At least two people were killed and 19 others injured from a Russian drone attack in northern Ukraine, the Sumy Regional Military Administration said.

An administrative building and two apartment buildings were damaged in the four drone strikes, officials said.

Four people have been hospitalized, according to officials. Two of the patients were listed in intensive care.

Ukrainian President Volodymyr Zelenskyy said in his daily evening address that the lack of air defense systems is part of the reason buildings were hit.

"The enemy is taking advantage of this," he said.

-ABC News' Ellie Kaufman

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