President Emmanuel Macron said on Thursday that France was entering a "new era" three years after the Russian-Ukrainian war and that he planned to tell US President Donald Trump that he could not "be weak" with Vladimir Putin.

Macron also defended Volodymyr Zelensky, the embattled leader of Ukraine, speaking ahead of a planned visit to the White House to meet Trump next week.

Macron has sought to coordinate a European response to Washington's policy shift in US-Russia relations, hosting this week two emergency meetings with leaders of EU and non-EU nations, including Germany, Britain, Canada, and Norway.

He said he wanted the French to grasp the magnitude of the threat coming from the Kremlin, calling Russia "an existential threat to Europeans."

In a Q&A session on social media on Thursday, Macron, 47, declared that France was embarking on a "new era."

"We are entering an era in which each of us must ask what we can do for the French nation and the Republic," Macron said after discussing Ukraine with party leaders earlier in the day.

Trump has sent shock waves around Europe by saying he is ready to resume diplomacy with Putin to end Russia's war against Ukraine, over the heads of European countries and Kyiv.

Trump will meet in Washington with Macron on Monday and British Prime Minister Keir Starmer on Thursday next week, the White House said.

"I'm going to tell him, 'You can't be weak with President Putin. That's not who you are, it's not your trademark, it's not in your interest," Macron said.

Meanwhile, the Kremlin said that any British plan to send troops to Ukraine as part of a potential peacekeeping mission would be unacceptable for Russia and that it was monitoring statements by Starmer with concern.

Russian Foreign Minister Sergei Lavrov said this week that Moscow views as a "direct threat" the idea of having Nato member troops on the ground in Ukraine, even if they operate there under a different flag. (AFP/Reuters)