U.S. President Joe Biden asked French President Emmanuel Macron to make the offer of a summit between Biden and Russian President Vladimir Putin to Putin, said an official from the French Presidency.

"We're slowly changing the course of things. We're creating a diplomatic perspective the Kremlin accepts," said the French presidential adviser.

"He is a facilitator," added the French presidential adviser, commenting on Macron's role.

Earlier, Macron's office said Biden and Putin had agreed in principle to a summit over Ukraine, offering a possible path out of one of the most dangerous European crises in decades.

The Kremlin said Putin and Biden could set up a call or meeting any time but there were no concrete plans yet for a summit.