Experts have welcomed Europe's efforts to seek a peaceful end to the Ukraine crisis, but cautioned that all sides will need to make compromises if a deal is to be made.

Michael Dunford, a professor emeritus at the University of Sussex in the United Kingdom, said: "The world has changed. Europe's relative military and economic power has declined. Its ability to exact unequal geopolitical and geoeconomic dividends has diminished. … Europe should recognize this new multipolar reality."

Europe should, therefore, "start by negotiating an indivisible security agreement with Russia, or better with Eurasia", he added.

Dunford's remarks come after days of intense political tension topped by a heated exchange on Friday at the White House between United States President Donald Trump and Ukrainian President Volodymyr Zelensky.

Zelensky, however, expressed his appreciation of the US for its support before attending a summit in London on Sunday, during which European leaders attempted to get peace talks involving Washington back on track.

UK Prime Minister Keir Starmer announced a four-step plan aimed at guaranteeing peace, with Europe doing the "heavy lifting" in terms of providing a peacekeeping force.

After the talks in London, Zelensky attempted to address criticism from the US that he was not grateful for Washington's support by writing on social media: "We understand the importance of America, and we are grateful for all the support we've received from the United States."

He added that there had "not been a day" when Kyiv did not appreciate Washington's backing, and that it felt "gratitude for the preservation of our independence".

However, Peter Mandelson, the UK's ambassador to the US, said Zelensky may need to do more. Ukraine may need to be the first side to declare a ceasefire, and Zelensky should enthusiastically accept Trump's proposed minerals deal, he said.

"We need a very radical reset," Mandelson told ABC News. "The reset has to consist of the US and Ukraine getting back on the same page, and President Zelensky giving his unequivocal backing to the initiative that President Trump is taking to end the war and to bring a just and lasting peace to Ukraine."

Meanwhile, French President Emmanuel Macron told Le Figaro newspaper that he wants a one-month pause of hostilities "in the air, at sea, and on energy infrastructure".

The pause would allow "negotiations that will take several weeks, and then, once peace is signed, a deployment" of peacekeeping soldiers would be possible, he said.

But the UK's Armed Forces Minister Luke Pollard told the BBC on Monday that Mandelson's comments were his private opinion and not the position of the UK government, and that London had not signed off on France's proposed one-month truce either.

Kremlin spokesman Dmitry Peskov said it looks as if the West lacks a "coordinated" plan.

"We see that the collective West has started to become less collective," he said at a daily news briefing. "A fragmentation of the collective West has begun, and the positions of different countries and groups of countries are becoming more nuanced."

Keith Bennett, a London-based senior international relations analyst, said that UK Prime Minister Starmer has taken on the role of mediating between the US, Europe and Ukraine, which is like "squaring a circle".

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