President Volodymir Zelenskiy voiced disappointment that Ukraine was not invited to join NATO on Tuesday, telling supporters in the Lithuanian capital: "Is this too big of a wish?"
"NATO will make Ukraine safer, Ukraine will make NATO stronger," he told the thousands of people, many waving Ukrainian flags, who gathered in central Vilnius, host to an alliance summit, as snipers stood guard on rooftops.
He thanked Lithuania for a "clear, honest and courageous position" in support of Ukrainian membership.
Shortly before the speech, NATO leaders agreed the alliance would extend an invitation to Ukraine to join the military alliance when "members agree and conditions are met."
Zelenskiy said earlier in the day it would be "absurd" if NATO leaders did not offer his country a timeframe for membership.
Speaking in Ukrainian, he told the crowd: "I travelled here today with belief in a decision, with belief in partners, with belief in a strong NATO, a NATO which does not doubt, which does not lose time, and does not look at any aggressor."
"I would wish for this belief to become a certainty - certainty in decisions that all of us deserve and which our every soldier expects, our every citizen, our every mother, our every child. And is this too big of a wish?" he asked.
NATO members in eastern Europe have backed Kyiv's stance, arguing that bringing Ukraine under NATO's collective security umbrella is the best way to deter Russia from attacking again.
Countries such as the United States and Germany have been more cautious, wary of any move that they fear could draw NATO into a direct conflict with Russia.
During the speech, Zelenskiy said: "No one should ever, ever look back to Moscow."
