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

Beginning in October, the U.S. will provide F-16 training to a small number of Ukrainian pilots and maintenance teams, Pentagon press secretary Brig. Gen. Pat Ryder said Thursday.

Ryder said "several" pilots and "dozens" of aircraft maintenance personnel will begin training at Morris Air National Guard Base in Tucson, Arizona, after they receive English training in September at Lackland AFB in San Antonio, Texas. The number of pilots and personnel will be determined by Ukraine.

"Although some Ukrainian pilots have English language skills we are anticipating that all the pilots coming to the United States will require some level of additional English language instruction, given the complexities and the specialized English that's required to fly these aircraft," said Ryder.

Sabrina Singh, the Pentagon's deputy press secretary, told reporters earlier this week that the U.S. was open to the idea of training on F-16's if European countries reached capacity though she couldn't define what numbers would constitute capacity. Ryder on Thursday also wouldn't provide a number and said the U.S. wasn't going to wait for the Netherlands and Denmark to reach capacity.

"We know that as the Danes and the Dutch prepare to train those pilots that at a certain point in time in the future, capacity will be reached. So preemptively acknowledging that and leaning forward in order to to assist with this effort is the impetus for why we're doing this now," said Ryder.

Ryder wouldn't get into when F-16 deliveries to Ukraine might begin. Denmark's Prime Minister said over the weekend that the first Danish F-16's could arrive by New Year's.

-ABC News' Luis Martinez