The NATO summit in Vilnius showed that the NATO "alliance has finally returned to the schemes of the Cold War," the Russian Foreign Ministry said in a statement Wednesday.

"NATO consistently lowers the threshold for the use of force and strengthens the nuclear component in military planning," the statement added.

The Russian Foreign Ministry also noted NATO countries "promised to continue supplying more and more long-range weapons to Kyiv," saying they are doing so in order to "prolong the conflict."

-ABC News' Tanya Stukalova

Ukrainian President Volodymyr Zelenskyy said he received assurances that Ukraine will become a member of NATO and told reporters he believes it will happen "as soon as the security situation is stabilized," when answering questions after the conclusion of the NATO summit in Vilnius, Lithuania, on Wednesday.

When asked what Zelenskyy got out of the summit, he said he received "support from the leaders and an unambiguous statement that Ukraine will be in NATO."

"I believe that we will be in NATO as soon as the security situation is stabilized. In simple terms, the moment the war is over, Ukraine will definitely be invited to join NATO and Ukraine will definitely become a member of the alliance. I have not heard any other opinion today," Zelenskyy said.

-ABC News' Ellie Kaufman

Wagner forces are turning over weapons and military equipment to the Russian Armed Forces, the country's defense ministry said Wednesday.

More than 2,000 pieces of equipment and weapons were transferred to the Russian Armed Forces from Wagner forces, including hundreds of tanks, air defense systems, self-propelled artillery mounts, armored personnel carriers and more, the defense ministry said.

Among the equipment, dozens of units have never been used in combat before.

Russian forces also received more than 2,500 tons of various ammunition and about 20,000 small arms, the defense ministry said.

Separately, the Belarusian Interior Ministry has "begun talks seeking to invite Wagner Group members to train its troops," Interfax, a Russian news agency, reported Wednesday.

-ABC News' Ellie Kaufman

Ukrainian President Volodymyr Zelenskyy said his in-person meeting with U.S. President Joe Biden in Lithuania’s capital on Wednesday was "very good" and "powerful."

Zelenskyy took to Twitter after their meeting ended in Vilnius, saying it lasted "twice as long as planned" and "was as meaningful as it needed to be."

"If the protocol had not stopped the meeting, we would have talked even longer," he tweeted.

Zelenskyy said their meeting covered "all the topics," including long-term support for Ukraine, weapons, politics and NATO membership.

"We clearly see how to end this war with our common victory," he added. "Thank you, Mr. President!"

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