In a joint declaration released Wednesday, the leaders of the Group of Seven reaffirmed their "unwavering commitment to the strategic objective of a free, independent, democratic and sovereign Ukraine."

"We will stand with Ukraine as it defends itself against Russian aggression, for as long as it takes," the joint declaration states.

G-7 leaders wrote in the joint declaration that they are working to "formalize" their "enduring support to Ukraine as it defends its sovereignty and territorial integrity, rebuilds its economy, protects its citizens, and pursues integration into the Euro-Atlantic community."

They also said they will "work with Ukraine" on an "enhanced package of security commitments and arrangements in case of future aggression to enable Ukraine to defend its territory and sovereignty."

The G-7 is an intergovernmental political forum consisting of Canada, France, Germany, Italy, Japan, the United Kingdom and the United States.

-ABC News' Ellie Kaufman

Ukrainian President Volodymyr Zelenskyy applauded the "outcome" of the annual NATO summit on Wednesday, describing the new commitments to his country as a "significant security victory."

"Ukrainian delegation is bringing home significant security victory," Zelenskyy said in brief remarks alongside world leaders in Lithuana's capital. "For our country, for our people, for our children."

Zelenskyy's laudatory tone was a sharp departure from his comments on Twitter the previous day. He told reporters that the long-term commitments announced by G-7 leaders on Wednesday would "absolutely" open "new security opportunities" and that he was "grateful."

"I thank everyone who made it possible," he added.

-ABC News' Cheyenne Haslett

G-7 leaders including U.S. President Joe Biden stood alongside Ukrainian President Volodymyr Zelenskyy in Lithuania's capital on Wednesday to announce a new long-term security package for Ukraine's future, while reaffirming that Kyiv has a place in NATO -- but not yet.

"All our allies agreed Ukraine's future lies in NATO. That's not a surprise to any of us, I don't think. I hope it's not a surprise to you, Mr. President," Biden said, turning to Zelenskyy during the press conference in Vilnius.

"Ukraine continues to make progress on necessary reforms," he added. "But we're not waiting for that process to be finished to make the long-term commitments that we're making to Ukraine security."

The U.S. commander in chief said he and Zelenskyy discussed what guarantees could be made to Ukraine during his visit to Kyiv earlier this year.

"Today, the members of the G-7 are launching the Joint Declaration of Support for Ukraine to make it clear that our support will last long into the future," Biden told reporters. "This starts the process by which each of our nations and any other nation who wishes to participate will negotiate long-term bilateral security commitments with and to Ukraine."

"We're going to help Ukraine build a strong, capable defense across land, air and sea," he added, "from which will be a force of stability in the region and deter against any and all threats."

-ABC News' Molly Nagle

Ukrainian President Volodymyr Zelenskyy arrived for his first NATO summit meeting in Lithuania's capital on Wednesday where he received a jovial welcome from world leaders eager to shake his hand -- a mood in keeping with the more conciliatory tone Zelenskyy has struck since landing in Vilnius.

The Ukrainian leader ultimately made a beeline for U.S. President Joe Biden, as NATO Secretary General Jens Stoltenberg created a path for him through the crowd of world leaders. The two men -- Biden in a suit and Zelenskyy in a dark green polo -- greeted each other with smiles and shook hands before chatting briefly.

Everyone eventually took their seats for the meeting of the NATO-Ukraine Council -- the first of its kind -- and Stoltenberg began his remarks with a warm welcome to Zelenskyy, whom he called "our dear friend."

"Welcome to this first meeting of the NATO-Ukraine Council," Stoltenberg said. "This is truly a historic moment, allies and Ukraine sitting side-by-side as equals to address our common vision of Euro-Atlantic security."

"And I'm really honored to welcome in our midst our dear friend, Volodymyr Zelenskyy, president of Ukraine. Welcome to Lithuania and it's great to have you here," he added.

Stoltenberg proceeded to give a very clear message about where NATO stands on Ukrainian membership, though no details on the pathway as has been a point of contention. He noted the summit has "reaffirmed that Ukraine will become a member of the alliance and we have made decisions to bring Ukraine closer to NATO."

"Today, we meet as equals," he said. "And I look forward to the day we meet as allies."

-ABC News' Cheyenne Haslett