US President Donald Trump’s suggestion of security guarantees for Ukraine is a “breakthrough” on the path to peace, NATO’s secretary general says.

Trump met one-on-one with Ukraine President Volodymyr Zelensky at the White House on Tuesday (AEST) followed by a roundtable discussion with European leaders.

Zelensky and Trump expressed hope that their meeting could lead to trilateral talks with Russian President Vladimir Putin to bring an end to Moscow’s war on Ukraine.

Asked about giving Ukraine security guarantees as part of a peace settlement, Trump said: “We will give them very good protection, very good security”.

“They want to give protection,” Trump said of European allies.

“They feel very strongly about it and we’ll help them out with it. I think it’s very important.”

Zelensky, who wore a dark suit – in contrast to the military outfit from his disastrous Oval Office meeting in February – said his latest talks with Trump had been the “best” so far.

He said the US was giving “strong signals” by raising the prospect of security guarantees.

NATO Secretary General Mark Rutte thanked Trump for the offer.

“The fact that you have said ‘I am willing to participate in the security guarantees’ is a big step, it’s really a breakthrough, and it makes all the difference,” said Rutte after the multilateral meeting with European leaders.

Volodymyr Zelensky said he had ‘very good talks’ with Donald Trump. Photo: AAP

Tuesday’s meeting came after Trump met Putin on Saturday (AEST) and changed his tune on seeking a ceasefire, instead pushing to secure a peace deal.

However, German Chancellor Friedrich Merz said all leaders at the meeting wanted a ceasefire in Ukraine.

“I can’t imagine that the next meeting would [take] place without a ceasefire, so let’s work on that, and let’s try to put pressure on Russia,” he said.

Trump appeared to quibble by responding “we’ll see how that works out” after Zelensky and Putin meet.

“If everything works out today, we’ll have a trilat,” Trump said, referring to possible three-way talks between himself, Zelensky and Putin.

“We’re going to work with Russia, we’re going to work with Ukraine.”

Trump also said he planned to talk to Putin after his meetings with Zelensky and European leaders.

Zelensky also expressed openness to trilateral talks.

“We are ready for trilateral, as [the] President said,” Zelensky said at the start of his meeting with Trump.

“It’s a good signal about trilateral. I think this is very good.”

Trump hosts Zelensky and European leaders at the White House. Photo: AAP

The Europeans leaders in Washington were European Commission President Ursula von der Leyen, French President Emmanuel Macron, British Prime Minister Keir Starmer, German Chancellor Friedrich Merz, Italian Premier Giorgia Meloni, Finnish President Alexander Stubb and NATO Secretary-General Mark Rutte.

They were left out of Trump’s summit with Putin on Saturday (AEST), and they want to safeguard Ukraine and the continent from any widening aggression from Moscow.

Many arrived at the White House with the explicit goal of protecting Ukraine’s interests — a rare show of diplomatic force.

By coming as a group, they hoped to avoid debacles like Zelensky’s February meeting in the Oval Office, where Trump chastised him for not showing enough gratitude for US military aid.

The meetings are also a test of America’s relationship with its closest allies after the European Union and Britain accepted Trump’s tariff hikes, partly because they wanted his support on Ukraine.

Ahead of the meeting, Trump suggested that Ukraine could not regain Crimea, which Russia annexed in 2014, setting off an armed conflict that led to its broader 2022 invasion.

Trump’s sit-down in Alaska with Putin yielded the possible contours for stopping the war in Ukraine, though it was unclear whether the terms discussed would ultimately be acceptable to Zelensky or Putin.

On the table for discussion with European leaders were possible NATO-like security guarantees that Ukraine would need for any peace with Russia to be durable.

Putin opposes Ukraine joining NATO outright. But Trump’s team claims the Russian leader is open to allies agreeing to defend Ukraine if it comes under attack.

“Clearly there are no easy solutions when talking about ending a war and building peace,” Meloni said.

“We have to explore all possible solutions to guarantee peace, to guarantee justice, and to guarantee security for our countries.”

The European leaders were aiming to keep the focus during the White House talks on finding a sustainable peace and believed forging a temporary ceasefire was not off the table, according to a European official.

-with AAP