China announced plans on Friday to restrict exports of graphite, an essential ingredient in building batteries for electric vehicles, on national security grounds, according to the Ministry of Commerce and General Administration of Customs.

The move is a threat to President Joe Biden's goals for electrifying the U.S. car fleet.

The new rules, which are expected to be implemented in December, would require export permits for artificial graphite, including high-purity, high-strength, and high-density materials, and natural graphite. The announcement comes just days after the United States imposed additional limits on the types of semiconductors that American companies can sell to Chinese companies.

China stands as the world’s most prominent producer and processor of graphite, accounting for an estimated 65% of total production, according to the U.S. Geological Survey. The mineral is used virtually in all EV battery anodes, which are the negatively charged portion of the battery.