Ukraine will get an invitation to join NATO when all the allies agree and all the conditions are met, Secretary General Jens Stoltenberg said during a press conference from the NATO summit in Vilinus, Lithuania, on Tuesday.

NATO agreed to remove the required membership action plan, he added, which makes the process take only one step instead of two.

A NATO-Ukraine Council will also be launched, Stoltenberg announced. The first session is planned for Wednesday with participation from Ukrainian President Volodymyr Zelenskyy, he said.

Zelenskyy had criticized the process for joining NATO ahead of his trip to Lithuania, saying, "It’s unprecedented and absurd when timeframe is not set neither for the invitation nor for Ukraine's membership."

-ABC News' Fidel Pavlenko

President Volodymyr Zelenskyy again called on Tuesday for NATO to invite Ukraine to become a member, offering a strongly worded statement as the coalition leaders gathered for a summit in Lithuania.

Ukraine "deserves respect," Zelenskyy said in a statement posted on Twitter.

"It's unprecedented and absurd when time frame is not set neither for the invitation nor for Ukraine's membership," he said. "While at the same time vague wording about 'conditions' is added even for inviting Ukraine. It seems there is no readiness neither to invite Ukraine to NATO nor to make it a member of the Alliance."

Keeping Ukraine out of NATO amounts to a "motivation" for Russia to "continue its terror," he said.

"Uncertainty is weakness," he added.

Russia rebutted the statement a short while later.

"This is potentially very dangerous for European security. Indeed, it is fraught with great dangers, and those who will make this decision should be aware of that," Dmitry Peskov, a Kremlin spokesperson, said when asked to comment on Ukraine's possible fast-track admission to the coalition.

President Joe Biden will meet with Ukrainian President Volodymyr Zelenskyy at the NATO summit in Vilnius, Lithuania this week, an administration official told ABC News.

The meeting comes as Zelenskyy pushes for a spot in NATO, despite Biden's public comments this weekend that he doesn't think that's the right move at this moment.

Biden has instead suggested a relationship similar to Israel and the U.S., with strong security commitments.

-ABC News' Cheyenne Haslett and Molly Nagle

Turkey and Sweden have reached a deal to advance the latter country's bid to join NATO, according to NATO Chief Jens Stoltenberg.

"This is an historic step which makes all #NATO Allies stronger & safer," Stoltenberg tweeted along with a photo of him and the two leaders shaking hands.

Turkey and Sweden have agreed to work on "legitimate security concerns," according to NATO.

Sweden has resumed arms exports with Turkey and "will present a roadmap as the basis of its continued fight against terrorism in all its forms and manifestations," according to NATO.

The two countries agreed to set up economic cooperation through the Türkiye-Sweden Joint Economic and Trade Committee, NATO said.

-ABC News' Will Gretsky

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.