The British leadership said the meeting at Lamy's official country residence in Chevening would bring together advisers from the US, Europe and Ukraine to"discuss progress towards securing a just and lasting peace".

It is understood that the meeting was organised at the request of the US and is being attended by Vance, who is staying in Kent at the start of his holiday in the UK.

The meeting comes after Trump announced he would meet with Putin in Alaska on August 15 to discuss ending the war in Ukraine.

The US president had previously suggested that any peace deal would likely include"some exchange of territory" and suggested that it could include Ukraine giving up the Donetsk region.

He previously threatened to impose tougher customs tariffs on Russia if Putin did not agree to a ceasefire by Friday.

But Ukrainian President Volodymyr Zelensky has already rejected any proposal that would threaten Ukraine's territorial integrity, saying that Kyiv"will not give Russia any rewards for what it has done" and that "Ukrainians will not give their land to the occupier."

The Ukrainian Constitution prohibits the surrender of territory.

Zelensky also warned that any peace agreement that excludes Ukraine would lead to"dead solutions."

Before the meeting in Chevening, British Prime Minister Keir Starmer spoke with Zelensky by phone on Saturday morning.

The British government's press service reported that"both leaders welcomed President Trump's desire to end this barbaric war and agreed that we must continue to put pressure on Putin to end his illegal war."

"The Prime Minister concluded the conversation by reaffirming his unwavering support for Ukraine and its people," the British government said.

On Friday, Lamy held formal talks with Vance in Chevening, during which the war in Ukraine was expected to be discussed.