More than 20 nations supporting Ukraine have pledged to “take Russian oil and gas off the global market” as part of efforts to pressure President Vladimir Putin to end the war.

“We’re choking off funding for Russia’s war machine,” said UK Prime Minister Sir Keir Starmer, after hosting a summit of the “coalition of the willing” in London.

The UK and US have in recent days sanctioned Russia’s two biggest oil companies, while the EU targeted Moscow’s liquefied natural gas (LNG) exports.

Ukrainian President Volodymyr Zelensky, who was also in London, said “pressure” on Russia was the only way to stop the fighting. However, no long-range missile deliveries to Ukraine were announced at the summit.

Zelensky has long argued that US-made Tomahawks and European missiles would help make the war costs heavier for Moscow by hitting key military targets – including oil refineries and weapons depots – deep inside Russia.

But during last week’s talks in Washington, US President Donald Trump indicated to Zelensky that he was not ready to supply Tomahawks.

On Thursday, President Putin warned that if “such weapons are used to strike Russian Federation territory the response will be… overwhelming”.

Russia launched a full-scale invasion of Ukraine in February 2022.

Speaking at a joint press conference after the London summit, Starmer said Putin was “not serious about peace”, and therefore Ukraine’s allies agreed a “clear plan for the rest of the year” on supporting Ukraine.

The UK prime minister said this also included targeting Russia’s sovereign assets to “unlock billions to help finance Ukraine’s defence”. He gave no further details.

On Thursday, EU leaders agreed to help support Ukraine’s “financial needs” for the next two years – but stopped short of agreeing to use frozen Russian assets worth €140bn (£122bn).

Asked about a so-called “reparations loan” for Ukraine funded by the Russian assets, Danish Prime Minister Mette Frederiksen said she hoped a decision would be made by Christmas Eve

In London, the “coalition of the willing” also pledged to strengthen Ukraine’s air defences” amid almost daily Russian air assaults on Ukrainian civilians and energy infrastructure.

Zelensky warned that Russia “wants to make the winter cold a tool of torment”, adding that “they want to break us”.

Further support for Ukraine’s energy infrastructure was among the issues discussed at the summit – however, no specific announcements were made.

Ukraine and its western allies have publicly agreed with President Trump’s proposal that the fighting should be immediately frozen along the vast front line for negotiations to begin.

Russia has rejected this idea, repeating demands that Kyiv and its allies describe as de facto capitulation by Ukraine.