Biden hits out at Putin as he declares 'our unity will not falter' on Ukraine

Western allies “will not waver” in defence of Ukraine, US President Joe Biden pledged on Wednesday at the Nato summit in Lithuania, as he hit out at Russian President Vladimir Putin.

The US President cast the struggle against Russian aggression as one of the world's central challenges requiring a broad coalition of countries to stand in defence of freedom.

Mr Putin had expected Nato to “break”, but “he thought wrong”, Mr Biden said in the courtyard of Vilnius University.

“The defence of freedom is not the work of a day or a year. It's the calling of our lifetime – of all time,” he said.

“Our unity will not falter. I promise you.”

He added that Lithuania knows the “transformational power of freedom” after spending decades under Moscow's thumb.

Mr Biden drew parallels between the country's struggle to escape Soviet rule and Ukraine's ongoing fight to repel Russia's invasion, highlighting the importance of rallying allies to take on the challenge.

“America never recognised the Soviet occupation of the Baltic,” he said to an outpouring of cheers from a crowd of thousands in the university's courtyard, draped with American and Lithuanian flags.

Mr Biden has spent two days in Vilnius for the annual Nato summit, where members of the western military alliance pledged more support for Ukraine but stopped short of extending an invitation to the besieged country to join the alliance.

After meeting Ukrainian President Volodymyr Zelenskyy, who entered the summit demanding a clear path for his country to joining the alliance – something that was initially promised back in 2008 – Mr Biden said that other security guarantees agreed to at the summit would be even more significant.

Day two of Nato summit in Lithuania – in pictures

“One thing Zelenskyy understands now is that whether or not he’s in Nato now, it’s not relevant as long as he has commitments,” Mr Biden said, comparing the situation to how the US ensures Israel's security edge over its neighbours.

The President pointed to the US and allied response to Moscow's invasion as a model for how to respond to other global challenges, from climate change to the rise of China, saying nations' positions are stronger when they “build the broadest and deepest coalition”.

“Our commitment to Ukraine will not weaken,” he said. “We will stand for freedom today, tomorrow and for as long as it takes.”

Mr Biden will head next to Finland, the newest member of Nato, for a meeting of Nordic leaders.

During his speech, Mr Biden hailed an agreement to advance Sweden's membership in Nato after Turkish President Recep Tayyip Erdogan agreed to drop his objections.

“President Erdogan kept his word,” Mr Biden said.

But the US President's enthusiasm for expanding Nato has not extended to Ukraine.

He has expressed concerns over the country's readiness to join the alliance as well as fears that the West could be drawn into a wider conflict with Russia.

The competing priorities in the midst of Europe’s bloodiest war in generations created an undercurrent of friction even as Mr Biden and Mr Zelenskyy projected a united front when they met earlier on Wednesday.

Their public encounter had the vibe of two leaders clearing the air and each heaped praise on his counterpart.

Mr Biden lauded Mr Zelenskyy and Ukrainians for their courage by saying they have “been a model for the whole world to see”.

Mr Zelenskyy thanked Mr Biden and the American people for the billions of dollars in military assistance, saying that “you spend this money for our lives”.

Wearing a tie bearing the colours of the Ukrainian flag, Mr Biden acknowledged that Mr Zelenskyy has occasionally been unsatisfied by unfulfilled requests for weapons.

“The frustration, I can only imagine,” Mr Biden said.

“I know that you're many times frustrated about whether things get to you quickly enough, what's getting to you and how we're getting it. But I promise you, the United States is doing everything we can to get you what you need.”

Mr Biden also said the war had created a sense of unity about opposing international aggression.

“It’s bringing the world together,” he said.

“It’s a hell of a price to pay, but it’s bringing the world together.”

The meeting came after a few other encounters between Mr Biden and Mr Zelenskyy at the summit. They sat close to each other at the inaugural meeting of the Nato-Ukraine Council, a new forum that aims to give Kyiv a greater voice within the alliance.

And they shared the stage as the Group of Seven, which includes the world's most powerful democratic countries, announced plans for long-term security assistance for Ukraine.

But Wednesday afternoon was the first opportunity for Mr Biden and Mr Zelenskyy to sit down privately with their advisers after their public comments.

And by then, Mr Zelenskyy had softened his tone considerably.

En route to Vilnius on Tuesday, he had blasted Nato's vague plans for Ukraine's eventual membership, tweeting: “It’s unprecedented and absurd when a time frame is set neither for the invitation nor for Ukraine’s membership.”

US National Security Adviser Jake Sullivan said everyone “needs to look squarely at the fact” that allowing Ukraine to join Nato at this point “means war with Russia”.

“That is an inescapable fact,” he told CNN.

Mr Sullivan credited Mr Biden with ensuring that Nato is “more unified and more determined and more decisive than at any point”.

“That’s President Biden’s legacy when it comes to Nato, and it’s one that he can be very proud of,” he said.