US President Donald Trump on Monday said that Russia would accept security guarantees for Ukraine as part of a peace deal, as he hosted Volodymyr Zelensky and European leaders at the White House.

Trump expressed optimism over the chances of ending Russia war with Ukraine and said he was ready to hold a three-way meeting with Ukrainian leader Zelensky and Russian President Vladimir Putin, whom he met in Alaska last week.

Zelensky – who also met separately with Trump in the Oval Office for the first time since their acrimonious row there in February – said his talks with Trump on Monday were the "best" yet.

"In a week or two weeks, we're going to know whether or not we're going to solve this or is this horrible fighting going to continue," Trump said as he opened the meeting.

Trump had pushed Ukraine ahead of the meeting to give up Crimea and abandon its goal of joining Nato – both key demands made by Putin.

But the US president said his talks with Putin had made progress on the issue of security guarantees.

"In a very significant step, President Putin agreed that Russia would accept security guarantees for Ukraine," Trump said. "We're going to be considering that at the table, also who will do what essentially."

Trump said that during the White House talks on Monday they also "need to discuss the possible exchanges of territory" between Russia and Ukraine.

Reports had said Putin was pushing for Ukraine to cede its eastern Donbas region, much of which is still partly in Kyiv's hands, in exchange for freezing the frontline elsewhere.

Ukraine has rejected any such move.

Trump said he was ready to attend a trilateral meeting with Putin and Zelensky in the near future to reach a peace deal.

"I think if everything works out well today we'll have a trilat, and I think there will be a reasonable chance of ending the war when we do that," Trump said earlier as he sat in the Oval Office alongside Zelensky.

Zelensky hailed his meeting with Trump, saying it was "important that the United States gives such strong signals" about Western security guarantees.

The atmosphere was far calmer than when Trump and Vice President JD Vance berated Zelensky in front of TV cameras less than six months ago for not being "grateful" for US support.

Trump even complimented Zelensky on his black jacket, after the Ukrainian was criticised by right-wing media because he failed to change his trademark war-leader's outfit for a suit during the February visit.

The Europeans lined up to praise Trump as they called for a lasting peace to end Russia's invasion.

"I'm really excited. Let's make the best out of today," Nato chief Mark Rutte said as the US president went round the table asking them to comment.

French President Emmanuel Macron, however, called for a separate four-way meeting including Europeans to deal with a grinding conflict that is on their doorstep.

German Chancellor Friedrich Merz meanwhile contradicted Trump's call to go straight for a full peace deal instead of an immediate ceasefire, calling for a truce before any leaders' summit.

"Let's work on that and let's try to put pressure on Russia," Merz said. (AFP)