U.S. President Donald Trump told European leaders on Thursday that Europe must stop buying Russian oil that he said is helping Moscow fund its war against Ukraine, a White House official said, striking a combative tone amid slow diplomatic progress to end the fighting.

Trump joined a call of the "Coalition of the Willing" countries, led by French President Emmanuel Macron, who were meeting in Paris on security guarantees for Kyiv in the event of a peace deal with Russia.

"President Macron and European leaders called President Trump into their ‘Coalition of the Willing' meeting. President Trump emphasized that Europe must stop purchasing Russian oil that is funding the war - as Russia received 1.1 billion euros in fuel sales from the EU in one year," the official said.

The European Commission has proposed legislation to phase out EU imports of Russian oil and gas by January 1, 2028, as Brussels seeks to sever its decades-old energy relations with Russia following its 2022 invasion of Ukraine.

Most European countries stopped importing Russian crude in 2022 and Russian fuel in 2023. It was not immediately clear whether Trump was referring to crude imports by Hungary and Slovakia, which have continued, or imports of fuel made from Russian crude that is refined in third countries, such as India.

Trump also said in the call that "European leaders must place economic pressure on China for funding Russia's war efforts," the official said.

Trump has been frustrated at his inability to bring a halt to the fighting in Ukraine after he initially predicted he would be able to end the war swiftly when he took office last January.

He has withheld new sanctions on Russia and China, a top Russian oil buyer. But he has ramped up tariffs on U.S. imports from India, another top Russian energy consumer. Trump shrugged off talks this week between Chinese President Xi Jinping and Russian counterpart Vladimir Putin, but also said the leaders might be conspiring against the U.S.

The U.S. president also continues to press Europeans to absorb more of the burden for their defense and is reluctant to commit more American support to a war that he wants to end.

The White House official said Ukrainian President Volodymyr Zelenskiy and European Commission President Ursula von der Leyen were among the leaders on the call.

"The 'Coalition of the Willing' meeting was on security guarantees for Ukraine. President Trump questioned their seriousness while they continue to fuel Russia's economy and war. The president made clear that this is not his war, and the Europeans must step up as well," the official said.

Source: Investing.com