NATO leaders on Tuesday crushed Ukrainian President Volodymyr Zelensky's aspirations for a clear schedule for joining the alliance, saying they would only extend an invitation to join if "conditions are met."

At a NATO conference in Vilnius, Secretary-General Jens Stoltenberg emphasized that the alliance had never used "stronger language" to support Ukraine in its tough battle against Russia, although leaders vowed that "Ukraine's future is in NATO," vowing in a statement that they would extend an invitation to Kiev when conditions are met.

However, the refusal to move any further than a 2008 pledge on future membership proved to be a cruel blow to Zelensky, who was in Vilnius to push his bid further.

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Zelensky Tweeted that there was "no readiness neither to invite Ukraine to NATO nor to make it a member of the alliance. This means that a window of opportunity is being left to bargain Ukraine's membership in NATO in negotiations with Russia. And for Russia, this means motivation to continue its terror," he added.

Zelensky added that "NATO will give Ukraine security, Ukraine will make NATO stronger," asserting that uncertainty is a weakness.

While Zelensky addressed the meeting in Vilnius, Russia announced that its forces advanced more than 1.5 kilometers on the eastern front.

With Zelensky's dreams for a membership timeline dashed, Western diplomats emphasized that there would be a larger package of support ideas meant to give Ukraine a military advantage in the war.

Chancellor Olaf Scholz of Germany said the G7 group of major industrialized nations will publish a declaration on long-term support that would kick in after "peace is obtained." This is anticipated to be confirmed on Wednesday, following the conclusion of the NATO meeting.

President Emmanuel Macron also said France will join the United Kingdom in sending long-range SCALP or Storm Shadow cruise missiles to Ukraine, allowing it to hit Russian targets far behind the front lines.

Furthermore, Denmark and the Netherlands announced that an 11-nation coalition will begin training Ukrainian pilots to fly F-16 fighter planes next month, with a new training base to be established in Romania.

Read more: Two EU members oppose Ukraine’s candidacy: Bloomberg

Biden, who is scheduled to meet with Zelensky on Wednesday, has stated that there is no consensus to award Kiev membership while the confrontation with Russia is ongoing since this would draw NATO directly into the fight.

Alliance leaders approved new regional strategies against any future Russian attack and agreed to increase defense budget objectives.

They decided that their previously set target of spending 2% of national GDP on defense would become the bare minimum.

According to the summit's communique, "We do so recognizing more is needed urgently to sustainably meet our commitments as NATO allies," adding that "we affirm that in many cases, expenditure beyond 2 percent of GDP will be needed in order to remedy existing shortfalls and meet the requirements."

The communique added that NATO and allies will "continue to improve IAMD [NATO Integrated Air and Missile Defence] capabilities, such as surveillance, interceptors, and command and control. We will continue to take into account the increasingly diverse and challenging air and missile threats ranging from simple Uncrewed Aerial Vehicles (UAVs) to sophisticated hypersonic missiles."

Circumstances to use nuclear weapons 'extremely remote'

The communique also stated that circumstances in which the alliance will utilize nuclear weapons are "extremely remote", claiming that the goal of the alliance is a "safer world for all" and that any use of nuclear weapons against NATO would "fundamentally alter the nature of a conflict."

The alliance also vowed to strengthen training and drills in order to facilitate "greater coherence between conventional and nuclear components of NATO’s deterrence and defense posture across all domains and the entire spectrum of conflict."

In addition, "NATO and Allies continue to improve IAMD [NATO Integrated Air and Missile Defence] capabilities, such as surveillance, interceptors, and command and control. We will continue to take into account the increasingly diverse and challenging air and missile threats ranging from simple Uncrewed Aerial Vehicles (UAVs) to sophisticated hypersonic missiles," the communique said.

In a press conference, Stoltenberg stated that the most urgent task at hand was ensuring Ukraine prevails in the war because according to him, if it does not, then the discussion around its membership is useless.

Zelensky stated that will set off from the meeting in hopes that NATO's hesitation becomes confidence "in the solutions that we deserve."