Donald Trump has rowed back on an earlier claim that he will only meet with Vladimir Putin if Volodymyr Zelenskyy is also at the summit - as a US deadline for Moscow to avoid further sanctions arrives.
The Russian president said on Thursday that he hoped to meet the US leader next week, with the summit potentially taking place in the United Arab Emirates.
Follow the latest updates from the war in Ukraine
Mr Putin's announcement came on the eve of a White House deadline for Moscow to show progress towards ending the three-year-old war in Ukraine or suffer additional economic sanctions.
Asked on Thursday if his deadline for Friday would hold, Mr Trump said of Mr Putin: "It's going to be up to him. We're going to see what he has to say. It's going to be up to him. Very disappointed."
Asked if Mr Putin needed to meet Volodymyr Zelenskyy in order to meet him, Mr Trump said: "No, he doesn't."
Sky News' US correspondent David Blevins said it was "very difficult to gauge the prospect for a meeting", with the last few days having left a number of questions unanswered - notably whether Russia is really more inclined to a ceasefire, and whether Mr Putin is ready to sit down with Mr Zelenskyy.
"It's difficult to see why Putin would be prepared to dilute his red lines at this point," Blevins said.
Two White House officials and a senior administration official have told Sky News that secondary sanctions on Russia are still expected to be implemented on Friday.
Meanwhile, Mr Trump has said on his Truth Social account that he will be hosting the president of Azerbaijan, Ilham Aliyev, and the prime minister of Armenia, Nikol Pashinyan, at the White House for an "official Peace Signing Ceremony" on Friday.
He added: "These two Nations have been at War for many years, resulting in the deaths of thousands of people. Many Leaders have tried to end the War, with no success, until now, thanks to 'TRUMP'."
Mr Trump has long been hoping to add Ukraine to the list of wars he boasts of having stopped, claiming during the election last year he could do so in a single day, but has been frustrated since returning to office.
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Putin suggests he won't meet with Zelenskyy
It comes after a White House official told the Associated Press that a US-Russian summit wouldn't happen if Mr Putin did not agree to meet with Ukrainian president Mr Zelenskyy, but the official later said it only made it less likely.
When asked about the prospect of meeting with Mr Zelenskyy, Mr Putin said on Thursday: "I have already said many times that I have nothing against it in general, it is possible."
However, he distanced himself from any such meeting happening soon, adding: "But certain conditions must be created for this. But unfortunately, we are still far from creating such conditions."
Read more:
What could happen when Trump and Putin meet?
Could Trump be close to ending the war in Ukraine?
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White House Press Secretary Karoline Leavitt has said Mr Trump wants to meet both leaders because he wants this "brutal war to end".
She added: "The White House is working through the details of these potential meetings and details will be provided at the appropriate time."
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It is understood that the White House is preparing for the possibility of a bilateral or trilateral meeting as it remains unclear whether Mr Putin will be prepared to meet with the Ukrainian leader.
Mr Zelenskyy said he had phone conversations with several European leaders on Thursday amid a flurry of diplomatic activity - as the Ukrainian government fears being sidelined by direct negotiations between Washington and Moscow.