Former U.S. President Donald Trump issued a pointed warning to Ukrainian President Volodymyr Zelensky on Sunday, accusing him of attempting to withdraw from a key agreement involving rare earth minerals — a move Trump said could carry serious consequences.

“He’s trying to back out of the rare earth deal, and if he does that, he’s got some problems—big, big problems,” Trump told reporters, without providing further details.

Though Trump did not specify the exact terms or timeline of the deal, rare earth elements are vital components in sectors such as defense, electronics, and renewable energy. Ukraine’s mineral reserves — among the most abundant in Europe — have made it a significant player in the global supply chain for critical raw materials.

There has been no formal response from the Ukrainian government or confirmation that any withdrawal is being considered. Zelensky’s administration has yet to publicly comment on Trump’s remarks.

The agreement in question may be part of broader U.S.-Ukraine cooperation on securing critical minerals, especially as Western nations seek to reduce dependency on China for these strategic resources. A breakdown in such a deal could have implications for bilateral relations and wider geopolitical competition over resource security.

The former president’s comments come at a delicate moment, as Ukraine navigates economic and security pressures amid its ongoing war with Russia. Trump has repeatedly expressed skepticism over the extent of U.S. aid to Ukraine and has signaled a more transactional approach to foreign partnerships.

It remains to be seen whether President Zelensky will address Trump’s warning or clarify Ukraine’s position on the rare earth agreement.