Financial markets edged higher on the glimmer of hope for a diplomatic solution even as satellite imagery appeared to show Russian deployments closer to Ukraine's border, while sounds of fighting were heard on Monday in the east, where Ukrainian government forces are fighting pro-Russian separatists.
The office of French President Emmanuel Macron said in a statement he had pitched to both leaders a summit on "security and strategic stability in Europe." In a statement, the White House said Biden had accepted the meeting "in principle" but only "if an invasion hasn't happened".
"We are always ready for diplomacy," White House Press Secretary Jen Psaki said. "We are also ready to impose swift and severe consequences, should Russia instead choose war."
Messages seeking comment from the Kremlin and the office of Ukrainian President Volodymyr Zelenskiy were not immediately returned early on Monday.
Few details of the proposed summit, announced after a volley of phone calls between Macron, Biden, Putin, Zelenskiy, and British Prime Minister Boris Johnson, are clear.
Macron's office and the White House said the substance of the plan would be worked out by U.S. Secretary of State Antony Blinken and Russian Foreign Minister Sergei Lavrov during their meeting planned for Feb. 24.
What role Ukraine would play in the summit, if any, was also uncertain.
A Biden administration official said in an email that the summit was "completely notional" as the timing and format had yet to be determined.
EU foreign policy chief Josep Borrell said there was a pressing need for talks to avoid war, while Germany said Russia should come back to the negotiating table.
While oil prices fell, Asian share markets pared losses and Wall Street futures rallied on news of the possible summit, Michael McFaul, a former U.S. ambassador to Russia, said he was sceptical it would happen.
"But if Biden and Putin did meet, they should invite (Zelenskiy) to join," he said in a message posted on Twitter.
News of Macron's proposal comes after a week of heightened tension spurred by Russia's military buildup.
Russian forces have been massing around its neighbour since late last year, in what Western countries say is a prelude to an invasion that could come at any moment.
