Ukraine’s President Volodymyr Zelensky, center, and Lithuania’s President Gitanas Nauseda, right, wave after addressing the public during an event on the sidelines of a NATO summit in Vilnius, Lithuania, on Tuesday. Ukrainian President Volodymyr Zelensky blasted as “absurd” the absence of a timetable for his country’s membership in NATO, injecting harsh criticism into a gathering of the alliance’s leaders that was intended to showcase solidarity in the face of Russian aggression. Pavel Golovkin/Associated Press

VILNIUS, Lithuania — NATO leaders said Tuesday that they would allow Ukraine to join the alliance “when allies agree and conditions are met” – a pronouncement that came just hours after President Volodymyr Zelensky blasted the organization’s failure to set a timetable for his country as “absurd.”

Instead, alliance leaders decided to remove obstacles on Ukraine’s membership path so that it can join more quickly once the war with Russia is over.

“We reaffirmed Ukraine will become a member of NATO and agreed to remove the requirement for a membership action plan,” NATO Secretary-General Jens Stoltenberg told reporters, referring to a key step in the process that involves advice and assistance for countries seeking to join.

“This will change Ukraine’s membership path from a two-step path to a one-step path,” Stoltenberg said.

Although many NATO members have funneled arms and ammunition to Zelensky’s forces, there is no consensus among the 31 allies for admitting Ukraine into NATO’s ranks.

Zelensky pushed back sharply against the decision as he headed to the annual NATO summit in Vilnius.

“It’s unprecedented and absurd when a time frame is set neither for the invitation nor for Ukraine’s membership,” Zelensky tweeted. “While at the same time, vague wording about ‘conditions’ is added even for inviting Ukraine. It seems there is no readiness to invite Ukraine to NATO or to make it a member of the Alliance.”

NATO membership would afford Ukraine protection against a giant neighbor that annexed its Crimean Peninsula almost a decade ago and more recently seized vast swaths of land in the east and south. Joining NATO would also oblige Kyiv to reform its security institutions, improve governance and curb corruption – work that would also ease the country’s path into the European Union.

Asked about Zelensky’s concerns, Stoltenberg said the most important thing now is to ensure that his country wins the war, because “unless Ukraine prevails there is no membership to be discussed at all.”

The broadside from Zelensky could renew tensions at the summit shortly after it saw a burst of goodwill following an agreement by Turkey to advance Sweden’s bid to join NATO. Allies hope to resolve the seesawing negotiations and create a clear plan for the alliance and its support for Ukraine.

The Ukrainian president, who was to meet Wednesday with U.S. President Biden and other NATO leaders, expressed deep frustration in an emotional speech in downtown Vilnius.

“Today I started my journey with faith in solutions, with faith in strong partners, with faith in NATO … in a NATO that does not hesitate, that does not waste time and does not look over their backs at any aggressor,” Zelensky said.

“I would like this faith to become confidence, confidence in the decisions that we deserve, all of us – every soldier, every citizen, every mother, every child,” he said. “Is that too much to ask?”

Sharp divisions have emerged within the alliance over Ukraine’s desire to join NATO, which was promised back in 2008 even though few steps were taken toward that goal.

In addition, the Baltic states – including Lithuania, which is hosting the summit – have pushed for a strong show of support and a clear pathway toward membership for Ukraine.

However, the United States and Germany urged caution. Biden said last week that Ukraine was not ready to join. Members of NATO, he told CNN, need to “meet all the qualifications, from democratization to a whole range of other issues,” a nod toward longstanding concerns about governance and corruption in Kyiv.

In addition, some fear that bringing Ukraine into NATO would serve more as a provocation to Russia than as a deterrence against aggression.

Concretely, NATO leaders decided to launch a series of multiyear programs to bring Ukraine’s Soviet-era military equipment and doctrines up to modern standards so the country can operate fully with the alliance.

On Wednesday, the leaders and Zelensky are set to launch a new, upgraded forum for their cooperation: a NATO-Ukraine Council, where all parties can convene crisis talks if their security is threatened.

To fast-track its future membership, the leaders agreed to do away with a membership action plan for Ukraine, a program often seen as mandatory for aspiring nations to undertake.

Known in NATO parlance as a MAP, the action plan involves a tailor-made package of advice, assistance and practical support for countries preparing to join NATO. Bosnia, for example, is currently taking part in one.

Pressed by reporters to say what kind of conditions are being placed on Ukraine joining, Stoltenberg said: “We want modern defense and security institutions.”

The dispute over Ukraine stands in contrast to a hard-fought agreement to advance Sweden’s membership. The deal was reached after days of intensive meetings, and it’s poised to expand the alliance’s strength in Northern Europe.

“Rumors of the death of NATO’s unity were greatly exaggerated,” White House national security adviser Jake Sullivan told reporters triumphantly on Tuesday.

According to a joint statement issued when the deal was announced, Turkish President Recep Tayyip Erdogan will ask Turkey’s parliament to approve Sweden joining NATO.

Hungarian Prime Minister Viktor Orban, another holdout, is expected to take a similar step. Hungary’s foreign minister said Tuesday that his country’s ratification of Sweden’s NATO membership was now just a “technical matter.” Erdogan has not yet commented publicly.

The outcome is a victory as well for Biden, who has touted NATO’s expansion as an example of how Russia’s invasion of Ukraine has backfired on Moscow.

Finland has already become the 31st member of the alliance, and Sweden is on deck to become the 32nd. Both Nordic countries were historically nonaligned until the war increased fears of Russian aggression.

Kremlin spokesman Dmitry Peskov told reporters that NATO’s expansion is “one of the reasons that led to the current situation.”

“It looks like the Europeans don’t understand their mistake,” Peskov said. He warned against putting Ukraine on a fast track for NATO membership.

“Potentially it’s very dangerous for the European security. It carries very big risks,” Peskov said.

Erdogan met with Biden on Tuesday evening but remained mum on the deal to advance Sweden’s membership in NATO.

Although Biden made a reference to “the agreement you reached yesterday,” Erdogan said nothing about it. It was a conspicuous omission from Erdogan, who has not commented on the issue publicly during the summit.

However, Erdogan appeared eager to develop his relationship with Biden. He said previous meetings were “mere warm-ups, but now we are initiating a new process.”

The Turkish president has been seeking advanced American fighter jets and a path toward membership in the European Union. The White House has expressed support for both, but publicly insisted that the issues were not related to Sweden’s membership in NATO.

The Biden administration has backed Turkey’s desire to buy 40 new F-16s as well as modernization kits from the U.S.

Biden is on a five-day trip to Europe, with the NATO summit as its centerpiece.

After the summit ends Wednesday, he will travel to Helsinki. On Thursday, he will celebrate Finland’s recent entry into NATO and meet with Nordic leaders.

Associated Press writers Aamer Madhani, Zeke Miller, Lisa Mascaro and Darlene Superville in Washington, Justin Spike in Budapest, Hungary, and Lorne Cook in Vilnius, Lithuania, contributed to this report.