British Prime Minister Keir Starmer told leaders gathered Sunday for a summit on the war in Ukraine that they need to step up and continue to support Kyiv and meet a “once in a generation moment”

It also puts further pressure on European allies as they scramble to find a common position and fill the void left by Washington. Prior to Zelenskiy, French President Emmanuel Macron and British Prime Minister Keir Starmer visited Washington to push Trump to offer US support for a European “backstop” to protect Ukraine from further attacks.

Ukrainian President Zelensky will join leaders in London for the meeting after an astonishing blowout between Kyiv and Washington on Friday.