Ukrainian President Volodymyr Zelenskiy is set to meet President Donald Trump and seal a deal for U.S. participation in Ukraine's mineral industry on Friday as Kyiv works to regain U.S. support to fight Russia's invasion while Trump opens talks with Moscow.

Zelenskiy, who gained billions of dollars' worth of U.S. weaponry and moral support from the Biden administration, is facing a sharply different attitude from Trump, who says he wants to quickly wind down the three-year war, improve ties with Russia and recoup billions spent to support Ukraine.

Trump has adopted a much less committed stance toward European security, a change in tone that has sent shockwaves across Europe and stoked fears in Kyiv and among its allies that it could be forced into a peace deal that favours Russia.

The agreement negotiated in recent days would open up Ukraine's vast mineral wealth to the United States but does not include explicit American security guarantees for Ukraine, a disappointment for Kyiv. Trump says the presence of Americans in business would serve as a form of guarantee.

How much the deal would be worth to the United States is not spelled out. Trump has said he expects to gain hundreds of billions of dollars. Zelenskiy has said he would not sign an agreement that would put his country in debt for generations.

Ukraine would contribute 50% of "all revenues earned from the future monetization of all relevant Ukrainian Government-owned natural resource assets" to a reconstruction fund jointly owned and managed by the United States and Ukraine.

The agreement does not specify how the funds would be spent, or identify specific assets it covers, though it says they would include deposits of minerals, oil and natural gas as well as infrastructure such as gas terminals and ports.

The Washington talks are a diplomatic boost for Zelenskiy who has repeatedly spoken of the importance of meeting Trump in person before the U.S. president holds talks with Russian President Vladimir Putin.

"The Ukrainians have been quite savvy at turning it round, and using this (the minerals deal) as an opening to engage the U.S.," said a senior Kyiv-based European diplomat, who requested anonymity to discuss sensitive matters.

Kyiv hopes the agreement will spur Trump to back Ukraine's war effort, and potentially even win support from Republicans in Congress for a new round of aid.

Ukraine has rapidly expanded its defence industry production but remains heavily reliant on foreign military assistance, while also struggling to replenish manpower as it battles a much larger foe.

While Ukraine repelled Russia's invasion from the outskirts of Kyiv and recaptured swathes of territory in 2022, Russia still controls around a fifth of Ukraine and has been slowly taking ground since a failed Ukrainian counteroffensive in 2023. Kyiv's troops hold a chunk of land in Russia's western Kursk region after a 2024 incursion.