Gen. Mark Milley, the U.S. military's top general, told reporters Friday that it's likely too early to tell the impact of the Wagner Group mutiny on Russian President Vladimir Putin.

"We want to know the answer to that question," Milley said when asked at the National Press Club if Yevgeny Prigozhin's mutiny had left Putin weakened. "I don't think we have evidence, conclusive evidence, either way, yet too early to tell."

Milley acknowledged that Ukraine's counteroffensive is making steady progress, but moving slowly -- something he said was not surprising given how tough of a fight it is.

"At the end of the day, Ukrainian soldiers are assaulting through minefields and in the trenches, and this is literally a fight for their life. So yes, sure, it goes a little slow, but that is part of the nature of war," Milley said.

He also noted that the U.S. is considering sending cluster munitions to Ukraine, though no decision has been made.

-ABC News' Luis Martinez

Russian Gen. Sergei Surovikin has apparently been detained, according to a U.S. official. Other details about his status are unclear.

The development follows reports from a senior U.S. official on Wednesday that Surovikin had engaged in discussions with Wagner Group leader Yevgeny Prigozhin about his plans to mutiny.

Prigozhin is now exiled in Belarus.

-ABC News' Luis Martinez

Former Vice President Mike Pence made a surprise trip to Ukraine on Thursday, projecting solidarity against Russia in a way, so far, unmatched by his Republican competitors in the 2024 presidential campaign.

"As I made clear to President [Volodymyr] Zelenskyy today, when I return home, whatever the future holds for me and my family, we're gonna stand for freedom," Pence told reporters. "And I'll do my part to make sure that America continues to stand for the courageous fighters here in Ukraine that are fighting to reclaim their freedom."

Pence visited the sites of atrocities in the early phase of the war, in Irpin and Bucha, among other stops, before meeting with Zelenskyy inside the presidential palace in the capital of Kyiv.

Read more about the trip here.

-ABC News' Libby Cathey and Guy Davies

Ukraine recorded the "largest deterioration" of peace worldwide in the latest global peace report from the international think tank Institute for Economics & Peace.

"The war in Ukraine had a significant impact on global peacefulness, with Ukraine and Russia having the largest and fifth largest deteriorations in peacefulness respectively," the report stated.

Since last year's report, Ukraine fell 14 places to 157th among the 163 countries covered by the report. Due to the conflict, 65% of men in Ukraine ages 20-24 have fled the country or died, according to the report.

-ABC News' Emma Ogao

The Ukrainian military has landed troops on the Russian-held eastern bank of the Dnipro River across from the city of Kherson, according to Russian reports.

Media posted online by pro-Russian accounts suggested small boatloads of Ukrainian soldiers have managed to establish a small beachhead at the foot of the destroyed Antonivskiy Road Bridge that spanned the river before Ukraine brought it down last year.

The size of the Ukrainian force on the bank is unclear, but Russian accounts suggested it was relatively small.

Some Russian accounts posted dramatic video showing fighting on the eastern bank, including what appears to be a Russian armored vehicle firing intensively at Ukrainian soldiers as it recovers Russian wounded.

The video was undated but Russian reports suggested around several dozen Ukrainian troops landed on June 24 and Russian airborne units have been trying to dislodge them since.

Another video shows a small boat carrying perhaps a dozen Ukrainian soldiers landing by the ruined bridge, coming under shell fire.

The Russian military blogger account, Two Majors, reported a small group of Ukrainian soldiers had succeeded in digging in around the bridge. It noted Russian forces had been forced to pull back to a distance from the bank because their positions had been flooded after the Kakhovka dam was blown up earlier this month.

Russian military bloggers said Russian aircraft and artillery were firing on the Ukrainians Monday.

If Ukraine is able to keep hold of its foothold, it will put further pressure on Russia’s forces in the south, already battling to hold back Ukraine’s counteroffensive on the Zaporizhzhia front.

-ABC News' Patrick Reevell