Russian President Vladimir Putin and US President Donald Trump could meet as soon as next week, the Kremlin says.
The White House confirmed Mr Trump was open to the meeting "because he wants this brutal war to end".
A White House official earlier cast doubt over whether the meeting would happen if Mr Putin did not also agree to meet Ukrainian President Volodymyr Zelenskyy.
But Mr Trump later said that was not the case. "I will do whatever I can to stop the killing," he said.
Asked if his Friday deadline remained in place for Mr Putin to agree to a peace deal, Mr Trump said: "It's going to be up to him. We're going to see what he has to say."
He added he was "very disappointed", but did not elaborate.
The White House official had told AP the US was still expected to impose sanctions on Russia on Friday, local time.
It followed a statement from Kremlin aide Yuri Ushakov, who said: "At the suggestion of the American side, an agreement was essentially reached to hold a bilateral meeting at the highest level in the coming days, that is, a meeting between President Vladimir Putin and Donald Trump.
"We are now beginning concrete preparations together with our American colleagues," he added in televised comments.
Although a date for a summit has not been set, Mr Ushakov said next week would be the target, noting that such events took time to organise.
The possible venue will be announced "a little later," he said.
He also played down the possibility of Mr Zelenskyy joining the summit meeting to discuss ending Russia's three-and-a-half-year invasion of Ukraine.
"We propose, first of all, to focus on preparing a bilateral meeting with Trump, and we consider it most important that this meeting be successful and productive," Mr Ushakov said.
After the Kremlin's announcement, Mr Zelenskyy said there was "still no public response from Russia" on where it stood on a ceasefire between the two countries.
"Ukraine is not afraid of meetings and expects the same brave approach from the Russian side," he said, referring to a meeting between him and Mr Putin.
The Ukrainian president spent Thursday in virtual meetings with a number of European leaders, including French President Emmanuel Macron and European Commission President Ursula von der Leyen.
An in-person meeting between Mr Putin and Mr Trump would be their first since the Republican president returned to office this year.
It would be a significant milestone in the war, though there was no promise that such a meeting would lead to the end of the fighting, since Russia and Ukraine remain far apart on their demands.
Professor of Russian politics at Kings College in London, Sam Greene, spoke to the ABC's The World on Thursday and said the meeting looked like it could be a "compromise solution".
He said one of the main questions people would be asking was the extent to which Mr Trump had become frustrated with Mr Putin.
"We have now seen for more than a month from Trump directly about his level of frustration with Putin," he said.
"It would be surprising or not entirely beyond the possibility again that they do lead to something real," he added.
Western officials have repeatedly accused Mr Putin of stalling for time in peace negotiations to allow Russian forces time to capture more Ukrainian land.
Mr Putin has in the past offered no concessions and will only accept a settlement on his terms.
Support for continuing the fight wanes in Ukraine
A new Gallup poll published on Thursday found that Ukrainians were increasingly eager for a settlement that ends the fight against Russia's invasion.
The enthusiasm for a negotiated deal is a sharp reversal from 2022 — the year the war began — when Gallup found that about three-quarters of Ukrainians wanted to keep fighting until victory.
Now, only about one-quarter hold that view, with support for continuing the war declining steadily across all regions and demographic groups.
The findings were based on samples of 1,000 or more respondents aged 15 and older living in Ukraine. Some territories under entrenched Russian control, representing about 10 per cent of the population, were excluded from surveys conducted after 2022 due to lack of access.
Since the start of the full-scale war, Russia's relentless pounding of urban areas behind the front line has killed more than 12,000 Ukrainian civilians, according to the United Nations.
On the 1,000-kilometre front line snaking from north-east to south-east Ukraine, where tens of thousands of troops on both sides have died, Russia's bigger army is slowly capturing more land.
ABC/wires
