European leaders closed ranks Sunday (Mar 2) in support of Kyiv at a London summit, where they pledged to spend more on security and assemble a coalition to defend any truce in Ukraine.

French President Emmanuel Macron, flying back from the summit, said in a newspaper interview that France and Britain were proposing a one-month truce.

Bringing together 18 allies, the talks came just two days after US President Donald Trump berated Ukraine's Volodymyr Zelenskyy at a live White House news conference.

UK Prime Minister Keir Starmer said that Britain, France "and others" would work with Ukraine on a plan to stop the fighting, which they would then put to Washington.

The London meeting came at a delicate moment for war-battered Ukraine, which faces uncertain backing from US President Donald Trump and is on the back foot against Russia's three-year invasion.

And Trump's row with Zelenskyy raised fresh questions over the US commitment to Ukraine and NATO.

Starmer said Europe found itself "at a crossroads in history".

"This is not a moment for more talk - it's time to act. It's time to step up and lead and unite around a new plan for a just and enduring peace," the premier added.

With no guarantee of US involvement, "Europe must do the heavy lifting", Starmer said. Several countries were ready to help defend any truce, he added - without naming them.

Macron, in an interview with France's Le Figaro newspaper, said he and Starmer were working on a one-month truce in Ukraine, "in the air, at sea".

He also suggested that European countries should raise their defence spending to between 3.0 and 3.5 percent of GDP to respond to Washington's shifting priorities.