Trump said he would certainly discuss the Russian invasion of Ukraine when he meets Xi on Thursday in South Korea.

"If President Trump manages to hold talks, make decisions, and reach an understanding with China to reduce imports of Russian energy, I think it will help all of us," Zelensky said at a press conference in Kyiv.

Trump has sought to leverage his personal chemistry with Russian leader Vladimir Putin to end the Ukrainian conflict, but has so far failed to make progress.

Last week, Trump sanctioned two of Russia's largest oil companies and pressed top energy buyers -- notably China and India -- to curb their purchases, which Washington and Kyiv say fund Russia's invasion.

"We support the US policy of exploring any opportunities to limit the supply of energy resources from Russia," Zelensky said.

"It concerns Ukraine, European security, and the entire world because they use the money from gas and oil to fund the war," he added.