US President Donald Trump said both Russian President Vladimir Putin and Ukrainian President Volodymyr Zelenskiy expressed a desire for peace in separate phone calls with him on Wednesday, and Trump ordered top US officials to begin talks on ending the war in Ukraine.

The conversations came after Trump's defence secretary earlier said Kyiv would have to give up its long-held goals of joining the Nato military alliance and regaining all of its territory seized by Russia, signalling a dramatic shift in Washington's approach to the conflict.

"He wants it to end. He doesn't want to end it and then go back to fighting six months later," Trump told reporters in the Oval Office after speaking with Putin for more than an hour.

"I think we're on the way to getting peace. I think President Putin wants peace, President Zelenskiy wants peace and I want peace. I just want to see people stop getting killed," he added.

Trump has long said he would quickly end the war in Ukraine, without spelling out exactly how he would accomplish this.

The Kremlin earlier said Putin and Trump had agreed to meet, and Putin had invited Trump to visit Moscow.

Trump said their first meeting would "probably" take place soon in Saudi Arabia.

In a post on his social media platform, he said Secretary of State Marco Rubio, CIA Director John Ratcliffe, national security adviser Michael Waltz and Middle East envoy Steve Witkoff would lead negotiations on ending the war.

Trump and Zelenskiy spoke after Trump's call with Putin, and Zelenskiy's office said the conversation lasted for about an hour.

"I had a meaningful conversation with @POTUS. We... talked about opportunities to achieve peace, discussed our readiness to work together ...and Ukraine's technological capabilities... including drones and other advanced industries," Zelenskiy wrote on X.

No Ukraine peace talks have been held since the early months of the conflict, now approaching its third anniversary.

European powers, including Britain, France and Germany, said on Wednesday they had to be part of any future negotiations on the fate of Ukraine, underscoring that only a fair accord with security guarantees would ensure lasting peace. They said they were ready to enhance support for Ukraine and put it in a position of strength. (Reuters)