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.
