British Prime Minister Keir Starmer has become the first European leader to say he is ready to put peacekeeping troops in Ukraine, making the commitment ahead of an emergency leaders' meeting in Paris to discuss Europe's role in a ceasefire.
US President Donald Trump stunned Ukraine and European allies last week when he announced he had held a call with Russian President Vladimir Putin without consulting them to discuss bringing an end to the three-year conflict.
Trump's Ukraine envoy, Keith Kellogg, said on Saturday Europe would not have a seat at the table for any peace talks. Washington sent a questionnaire to European capitals to ask what they could contribute to security guarantees for Kyiv.
Starmer, who is expected to travel to Washington to meet Trump next week, said on Sunday that Europe was facing a "once in a generation moment" for the collective security of the continent, and it must work closely with the United States.
He said Britain was ready to play a leading role in delivering security guarantees for Ukraine, including being ready to put "our own troops on the ground if necessary".
"The end of this war, when it comes, cannot merely become a temporary pause before Putin attacks again," he wrote in the Daily Telegraph newspaper.
French President Emmanuel Macron was due to host leaders from Germany, Italy, Britain, Poland, Spain, the Netherlands and Denmark, which will represent Baltic and Scandinavian countries, along with the European Union leadership and NATO Secretary General Mark Rutte.
Dozens of similar summits in the past have shown the 27-nation EU to be dithering, disunited and struggling to come up with a cohesive plan to end the Ukraine war on its doorstep.
Britain is not an EU member but has been a leading supporter of Ukraine in its fight to repel the Russian invasion. A peacekeeping force would raise the risk of a direct confrontation with Russia and stretch European militaries, whose arms stocks have been depleted by supplying Ukraine and who are used to relying heavily on US support for major missions.
EUROPE NEEDS TO 'DO MORE, BETTER'
A French presidency official said the acceleration in diplomacy meant Europe needed to do more and in a better way.
In the six-point questionnaire, seen by Reuters on Sunday, the US asked European allies in NATO what they would need from Washington to participate in Ukraine security arrangements.
"We believe that, as a result of the acceleration on the Ukrainian issue, and also as a result of what American leaders are saying, there is a need for Europeans to do more, better and in a coherent manner for our collective security," the official told reporters.
"These initiatives are an opportunity in the sense that they can help speed up the end of the war in Ukraine, but obviously we still need to agree and see under what conditions the end of the war can be achieved."
The discussion, he said, would look at "the security guarantees that can be given by the Europeans and the Americans, together or separately."
Peacekeepers would be just one element of the security guarantees being sought by Ukraine.
Some countries were unhappy that the Paris meeting was only for selected leaders and not a full EU summit, EU officials said.
The French presidency official said the meeting would facilitate future discussions in Brussels and at NATO.
"Everybody should be able to take part in the conversation," he said.