(Washington, Reuters) — The U.S. auto industry has warned that an imminent shortage of rare earth magnets from China could force American car factories to shut down within weeks.

In a previously undisclosed letter dated May 9, the Alliance for Automotive Innovation told Trump administration officials:
“If these rare earth elements and magnets cannot be reliably sourced, auto suppliers will be unable to produce critical vehicle components, including automatic transmissions, throttle bodies, alternators, various motors, sensors, seat belts, speakers, headlights, electric motors, power steering systems, and cameras.”

The letter emphasized that the normal operation of U.S. auto factories would be affected without these essential parts. “In severe cases, production may need to be reduced or even result in the shutdown of vehicle assembly lines.”

The Alliance represents major automakers including General Motors, Toyota, Volkswagen, Hyundai, and others. The Motor & Equipment Manufacturers Association (MEMA) also co-signed the letter.

China accounts for over 90% of the world’s rare earth magnet processing capacity. In April, China announced export controls on seven categories of rare earths, and its rare earth magnet exports dropped by half in the same month.

John Bozzella, CEO of the Alliance for Automotive Innovation, told Reuters on Friday (May 30) that the issue was discussed during earlier U.S.-China talks in Geneva, but the problem remains unresolved.

U.S. Trade Representative Katherine Tai told CNBC on Friday that while China has agreed to lift export restrictions on rare earth magnets to U.S. companies, it has been slow to follow through on that commitment.

Meanwhile, India’s Society of Indian Automobile Manufacturers (SIAM) also warned during a meeting with Indian officials last week that due to China’s export restrictions, their rare earth magnet inventory is nearly depleted, and they expect to be forced to suspend production by the end of May or early June.