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!"

The United States "is prepared to defend every inch of NATO territory," National Security Advisor Jake Sullivan said Wednesday, amid Russia's threats of military retaliation if Sweden and Ukraine officially join the alliance.

"At the end of the day, Russia does not get a vote in who joins NATO," Sullivan told ABC News' George Stephanopoulos during an interview Wednesday on "Good Morning America."

"If Russia does choose to test Article 5, President Biden has said he is prepared to defend every inch of NATO territory," he added. "And later tonight, when he addresses a large crowd in Vilnius in a speech about his vision for Euro-Atlantic security and for American leadership, he will reinforce this point about the sanctity of Article 5."

Article 5 of the NATO treaty states that the signed parties "agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all."

Sweden and Finland, which have historically embraced neutrality, applied for NATO membership together last year despite warnings from Moscow against doing so, as Russian forces invaded Ukraine. Finland officially joined the alliance in April following Turkish ratification, but Turkey and Hungary have yet to ratify Sweden’s membership. NATO Secretary-General Jens Stoltenberg announced Monday that Turkish President Recep Tayyip Erdogan has agreed to send Sweden’s NATO accession documents to Turkey’s Parliament for approval "as soon as possible," one of the last steps in the membership process.

Meanwhile, Ukraine is pushing hard for NATO membership as Russia’s war presses on. Stoltenberg announced Tuesday that the bloc "will issue an invitation for Ukraine to join NATO when allies agree and conditions are met," pledging to speed up the process by eliminating bureaucratic hurdles, but without offering a timeline.

"All 31 allies got together yesterday to say with one voice that Ukraine's future is in NATO. The real question is just how we work down the pathway to get them in," Sullivan told ABC News on Wednesday. "So the signal that NATO sent yesterday was very positive to Ukraine about its future prospects for joining NATO, and we will work in terms of the democratic and security sector reforms that are necessary. And in the meantime, we're not just going to sit around. We're going to provide Ukraine with the weapons and military assistance it needs to defend its territory against Russia and to deter future aggression from Russia."

Ukraine has requested F-16 fighter jets and long-range missiles to aid its counteroffensive against Russian forces. Sullivan said the U.S. has already taken steps with NATO allies to begin the training of Ukrainian pilots on F-16s, which "will take some time," and then the aircraft will be transferred to Ukraine "likely from European countries that have excess F-16 supplies." As for the long-range missiles, Sullivan said the U.S. will continue to look into the issue and discuss it with Ukraine.