Ukrainian President Volodymyr Zelenskyy has urged the United States to expand sanctions on Russian oil from two companies to the whole sector.
He also appealed for long-range missiles to hit back at Russia.
Zelenskyy was speaking in London for talks with two dozen European leaders who have pledged military help to shield his country from future Russian aggression if a ceasefire stops the more than three-year war.
A crowd waving Ukrainian flags greet Ukraine's President Volodymyr Zelenskyy and UK Prime Minister Keir Starmer arriving for the 'Coalition of the Willing' meeting in London with European leaders.
Hosted by the coalition's co-leader Keir Starmer, the talks aimed to step up pressure on Russian leader Vladimir Putin adding momentum to measures in recent days that have included a new round of sanctions from the US and European countries that take aim at Russia's vital oil and gas export earnings.
British Prime Minister Keir Starmer said: "First, we will act to take Russian oil and gas off the global market. Last week, the UK became the first country to sanction all of Russia's oil majors. On Wednesday, the US acted decisively to join us, together with further sanctions from the EU and we're choking off funding for Russia's war machine."
Starmer also remarked on major countries scaling back oil purchases from Russia. "I would also add that the measures or the movements in position by India and China in relation to Russian energy and oil in particular are also significant," he said.
Zelenskyy adding his country is carrying out its own campaign. "We are carrying out our own campaign of pressure with drones and missiles, specifically targeting the Russian oil sector."
He also called on the US to sanction all Russian oil companies, not just two. "There is one more important decision by the United States of America: sanctions against two large Russian oil companies...all Russian oil companies including Rosneft, Lukoil, Putin's own oil company and others must be blocked," he said.
This as NATO Secretary-General Mark Rutte said Putin's goals remain unchanged but he is running out of money, troops and ideas. "In Ukraine, Putin is gaining little ground on the battlefield and there are marginal gains. They are coming at a huge price, hundred of thousands of Russians are dying for Putin's deluded aggression.
Ukraine continues defending itself bravely, and our support to them is working. The truth is that Putin is running out of money, troops and ideas."