The Defense Department on Thursday became the largest shareholder in MP Materials, which owns the only rare earth mine in the U.S., amid a surge in demand for rare earths mined in the U.S. as China has curbed its rare earth exports amid a trade war with the U.S.

MP Materials has announced plans to expand rare earth mining and processing operations as Washington seeks to end its dependence on Chinese supplies.

A new trade agreement between the US and China has eased export restrictions on rare earth minerals, bringing relief to industries dependent on these critical materials.