The West is at a ?crossroads in history,? Britain?s Prime Minister Keir Starmer told European leaders at a pivotal summit in London on Sunday, as the continent sought to wrestle control of negotiations over the Russia-Ukraine war away from the US and present a united front amid a meltdown in relations between Kyiv and Washington.

This is not a moment for more talk. It?s time to act,? Starmer said after a monumental day of diplomacy in London, which saw leaders on the continent attempt to forge a path towards a ceasefire in Ukraine.

The urgency of the summit in London?s ornate Lancaster House was heightened after US President Donald Trump chastised Zelensky in the Oval Office, appalling the West and delighting Moscow in the process. Zelensky and an ensemble of European leaders were in attendance, at a moment of intense anxiety in the conflict.

Starmer told reporters he was working with France and a small number of other nations to craft a plan to stop the fighting, which would then be presented to the US.

French President Emmanuel Macron outlined the contours of such a plan in an interview with Le Figaro, saying that France and the United Kingdom have proposed a month-long limited ceasefire in Ukraine.

The initial phase of a French-British alternative peace deal for Ukraine would involve a month-long ?truce in the air, on the seas and energy infrastructures,? according to Macron speaking to the French outlet. The second phase, he said, would involve troops on the ground. CNN has reached out to Downing Street for comment.

The plan seems destined to rival the negotiation process that Trump?s administration opened with Russia last month, and suggests a tacit acceptance that bringing Trump and Zelensky to the negotiating table together could result in tensions combusting once more.

But it would still require American support, Starmer again reiterated during a Sunday press conference. He insisted the US was ?not an unreliable ally? after Trump?s extraordinary argument with Zelensky deeply spooked Europe.

The West will hope Sunday?s summit has revived momentum in a peace process that appeared to be slowly building this week, only to come crashing down in those nasty few minutes on Friday. It displayed European unity, and several leaders in attendance sought to correct a narrative that the continent was a bystander in the negotiations to end the war.

?In the end, a deal will have to involve Russia, of course it will, but we can?t approach this on the basis that Russia dictates the terms of any security guarantee before we?ve even got to a deal ? otherwise, we won?t make any progress at all,? Starmer said.

The UK and France have been attempting to put together a ?coalition of the willing? that would enter Ukraine after a deal is agreed. ?If a deal is done, it has to be a deal that is then defended,? Starmer said.

Zelensky applauded Sunday?s summit on X, saying that ?Europe?s unity is at an exceptionally high level, one that has not been seen in a long time.? In a separate statement, Zelensky said a potential peace deal should start with a prisoner exchange, ?and the return of children.? This, he said, would ?demonstrate Russia?s true intention for peace.?

Macron told Le Figaro that the advantage of the French-British proposed ceasefire is that it is easy to monitor. ?We know how to measure it,? he said, adding: ?in the event of a ceasefire, it would be very difficult to verify that the front is respected.?

Macron, who the outlet reports spoke with Trump on Friday, told Le Figaro that there will be ?no European troops on Ukrainian soil in the coming weeks.? The French newspaper also wrote that Macron does not believe in a ceasefire signed between the US and Russia because he is ?convinced that Vladimir Putin will seek to humiliate Ukraine.?

Zelensky said he was ?aware of everything? when asked if he knew about the proposal. He did not say whether he agreed to the proposed ceasefire.

Zelensky enjoyed a heartfelt welcome from Starmer on Saturday that could not be more different than the reception he endured at the White House. King Charles also met with Zelensky at his Sandringham estate on Sunday.

The earlier spectacle of the American president and vice president berating the leader of a war-torn ally added intensity to Sunday?s summit, which had initially been convened by Starmer to build on the progress achieved during a similar meeting in Paris last weekend.

Trump and JD Vance accused Zelensky of being ungrateful for American military support, for ?gambling with the lives of millions of people,? and risking ?World War III? by fighting Russia?s invading army in his country.

The scenes were Europe?s worst nightmare. ?Nobody wants to see that,? Starmer told the BBC on Sunday. He said he ?hit the phones? as soon as he watched the furious argument, adding: ?My driving purpose has been to bridge this.?

Ukraine?s leader will return to Kyiv with more than just warm words. On Saturday Britain announced an agreement to accelerate $2.8 billion worth of loans to Ukraine. The first tranche of funding is expected to be disbursed next week, according to the UK government.

In a Telegram post on Saturday, Zelensky said ?the money will go toward the production of weapons in Ukraine. This is the fair way: the one who started the war should pay.? He added that ?the loan will strengthen our defense capabilities.?

Then on Sunday, Starmer announced a new deal that allows Ukraine to use ?1.6 billion ($2 billion) of UK export finance to buy more than 5,000 advanced air defense missiles, which would be made in Belfast.

?We gather here today because this is a once-in-a-generation moment for the security of Europe and we all need to step up,? Starmer told leaders as he opened Sunday?s summit.

The meeting will have three goals, Downing Street said: Ukraine?s short-term needs, securing a ?lasting deal? to end the conflict, and ?planning for strong security guarantees.?

?I hope you know that we are all with you and the people of Ukraine for as long as it takes, everyone around this table,? Starmer told Zelensky during his opening remarks.

French President Emmanuel Macron, Canada?s outgoing leader Justin Trudeau, and the heads of several European countries, the European Union and NATO were all present.

Italian Prime Minister Giorgia Meloni told Starmer on Sunday it is ?very, very important that we avoid the risk that the West divides? over the war in Ukraine.

The two leaders may prove vital in corralling a peace process; both have developed strong relationships with Trump, and will be expected to use that influence to convince the president to listen to Europe?s proposals.

CNN?s Saskya Vandoorne, Catherine Nicholls, Svitlana Vlasova, Gul Tuysuz and Brice Laine contributed to this story. (CNN)

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