PARIS — French President Emmanuel Macron said the next two weeks will be “critical” for defining security guarantees for Ukraine following high-stakes peace talks on Monday.

“There is all the work that needs to be done beforehand on security guarantees. The next 15 days are absolutely critical for us to finalize the work with the Americans and give these security guarantees substance,” Macron said in an interview with French broadcaster LCI from Washington that aired on Tuesday.

Macron and several other European heavyweights interrupted their summer vacations to join Ukrainian President Volodymyr Zelenskyy for talks at the White House on Monday, on the heels of U.S. President Donald Trump’s meeting with Russian leader Vladimir Putin in Alaska on Friday.

In a series of interviews with French and American media, Macron praised Trump’s decision to, in the U.S. president’s words, provide Ukraine with a “very good security guarantee.”

“The big change in recent days is that he has acknowledged the need to guarantee Ukraine’s security,” Macron told Paris Match.

What that security guarantee entails is not yet clear, though Macron told LCI that “the British, French, Germans, Turks and others are ready to carry out operations, not at the frontline, not provocatively, but reassurance operations in the air, at sea and on land.”

Macron and British Prime Minister Keir Starmer will on Tuesday co-chair a videoconference of the Coalition of the Willing, a loose partnership of Western countries pledging support for Ukraine, “to follow up on yesterday’s meeting in Washington and continue the work begun on the issue of security guarantee,” according to the French president’s office.

Macron told LCI that “the British, French, Germans, Turks and others are ready to carry out operations, not at the frontline, not provocatively, but reassurance operations in the air, at sea, and on land.”

However, Macron cautioned against going for a quick win and taking the Kremlin at its word. He said in his LCI interview that Russia is a “destabilizing force” and a “a predator, an ogre at our door.”

“We want to make sure that this peace, and so this deal will be something which will allow the Ukrainians to recover their country and live in peace, to be sure the day after this peace deal that they will have sufficient deterrence power not to be attacked again, and to be sure for the Europeans that they will live in peace and security,” Macron told NBC News.

As Trump pushes for both a bilateral meeting between Putin and Zelenskyy and a trilateral in which he would join the duo, Macron pushed in his LCI interview for Geneva as a potential host, given its history as a neutral venue for international negotiations.

Macron said that Putin’s willingness — or refusal — to take part in the trilateral meeting with Zelenskyy and Trump would help “clear up ambiguities” and reveal whether the Russian leader was serious about making peace.