U.S. Vice President JD Vance has warned Russia’s full-scale invasion of Ukraine is not likely to come to an end “any time soon.”

Speaking during an interview on Fox News, Vance said on Thursday that President Donald Trump‘s administration was working to “find some middle ground” to stop a conflict that has been raging for more than three years.

“It’s not going anywhere … it’s not going to end any time soon,” Vance said.

His comments come shortly after the U.S. and Ukraine signed a long-awaited minerals deal, an agreement that Vance said showed the White House is making progress.

He later added that while he was “optimistic” of a breakthrough in peace talks, “it’s hard to say confident” because Russia and Ukraine will “have to take the final step.”

After months of tense negotiations, the U.S. and Ukraine on Wednesday signed an economic partnership that provides Washington with preferential access to some of Kyiv’s natural resources.

U.S. Secretary of the Treasury Scott Bessent said the “historic” agreement would allow the two countries to invest together to accelerate Ukraine’s economic recovery and help to “facilitate the end of this cruel and senseless war.”

For its part, Ukraine said the partnership was capable of delivering success for both Washington and Kyiv.

Since his inauguration in January, Trump has pushed for a minerals deal with Ukraine, saying an agreement to jointly develop and monetize Kyiv’s deposits of rare earths, critical minerals, oil, gas and other natural resources would act, effectively, as compensation for U.S. aid to Ukraine throughout the war with Russia.

Before his presidential victory last fall, Trump pledged to end Russia’s war with Ukraine in just “one day.”

U.S. Secretary of State Marco Rubio warned on Tuesday that Washington could step back from its mediation efforts unless Russia and Ukraine delivered “concrete proposals” on how to end the conflict.

The Kremlin on Wednesday reiterated previous statements that Russian President Vladimir Putin is open to peace talks with Ukraine.

— CNBC’s Holly Ellyatt contributed to this report.