U.S. cluster munitions have arrived in Ukraine, according to Joint Staff Director for Operations Lt. Gen. Douglas Sims.

Sims said that in contrast to Russia, Ukraine is aware of the possible danger to civilians, and does not intend to use them near population centers.

"I don't think that Ukrainians have any interest in using the cluster munitions anywhere near the civilian population, unlike the Russians," Sims told reporters.

-ABC News' Matt Seyler

Coming off a "very productive summit" with NATO allies, President Joe Biden offered a forceful dismissal of Vladimir Putin’s efforts to capture Ukraine during a joint press conference in Helsinki with Finnish President Sauli Niinisto.

"There is no possibility of him winning the war in Ukraine. He's already lost that war," Biden said.

Biden has made similar statements before about Putin’s chances of success, though it’s particularly notable coming off of his meeting with Ukrainian President Volodymyr Zelenskyy and his top military officials Wednesday.

Biden wouldn’t give a timeline for how long he thinks the war can continue, but he ruled out a yearslong offense.

"I don't think the war could go on for years for two reasons. No. 1, I do not think that Russia could maintain the war forever -- No. 1 in terms of their resources and capacity. No. 2, I think that there is going to be a circumstance where eventually, President Putin is going to decide it’s not in the interest of Russia economically, politically or otherwise to continue this war," Biden said.

"But I can't predict exactly how that happens," he continued. "My hope is and my expectation is you’ll see that Ukraine makes significant progress on their offensive and that it generates a negotiated settlement somewhere along the line."

-ABC News' Molly Nagle and Cheyenne Haslett

U.S. National Security Council spokesman John Kirby said Thursday that "it remains to be seen" whether Russia has recovered from last month's brief but chaotic mutiny and if it will have any notable effect on the fighting in Ukraine.

"We don't exactly know what transpired every minute of that event and we don't really know what kind of impact it's going to have on the war in Ukraine," Kirby told ABC News' George Stephanopoulos during an interview on "Good Morning America."

"As we speak, there hasn't really been that much of an effect on the fighting in Ukraine," he added. "The Russians are dug in. The Ukrainians are trying to claw back territory. We're still trying to help them win."

Ukrainian forces are in the midst of a counteroffensive, "all the way from the Donbas area down toward Zaporizhia to the south," according to Kirby.

"They're making halting progress, not as fast [or] as far as they'd like to go, but we're going to do everything we can to give them the tools and capabilities to succeed," he said. "It could be weeks, it could be months of hard fighting here as they try to claim back the rest of their country."

Russian Foreign Intelligence Director Sergey Naryshkin claims he had a phone conversation with CIA Director William Burns in late June, according to the Russian state media outlet TASS.

"The bulk of the conversation was focused on discussing Ukraine and events around it. We gave some thought to and deliberated on what should be done about Ukraine," Naryshkin claimed to the outlet.

The CIA declined to comment about the alleged call.

The alleged conversation lasted "about an hour," according to Naryshkin.

The Russian intel chief noted that arranging an in-person meeting between him and the CIA leader remained a possibility.

-ABC News' Anastasia Bagaeva

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