The Chinese government on Thursday announced broad new export controls on rare-earth magnets and their raw materials on grounds of national security.

The move comes before Chinese President Xi Jinping is expected to meet U.S. President Donald Trump later this month. Washington currently charges tariffs of 57.6 percent on Chinese goods.

Importers will need a government license to access certain rare-earth magnets but also refined metals and alloys that go into magnets.

Beijing exploited its dominance in raw materials — and specifically rare-earth elements like scandium, yttrium and dysprosium — against the U.S. earlier this year when the Trump administration declared prohibitive tariffs on Chinese goods.

The country controls the vast majority of rare-earth elements mining, refining and casting plus 90 percent of magnet production. Permanent magnets — as opposed to electromagnets — are used in electric vehicles, wind turbines, but also in U.S. military kit such as F-35 fighter jets and naval vessels.

China presented the new rules as necessary under itws nonproliferation commitments and “its consistent position of firmly upholding world peace and regional stability,” according to a government spokesperson on Thursday morning.

“In principle, export applications to overseas military users,” the text stipulates, “will not be approved.” It adds further limits on “end-users listed on the export control list and watch list” and subsidiaries.

In Europe, a new commercial-scale factory for magnets has just opened in Estonia to reduce the bloc’s dependency on China.