President Donald Trump threatened to increase China’s tariffs if Beijing doesn’t supply enough rare earth magnets to the U.S.

In a Monday press conference, Trump told reporters that he would increase tariffs if China withheld rare earth magnet exports. “They have to give us magnets, if they don’t give us magnets, then we have to charge them 200% tariffs or something,” he said.

“China intelligently went and they sort of took a monopoly of the world’s magnets,” he continued. “Nobody needed magnets until they convinced everybody 20 years ago ‘Let's all do magnets.’”

Rare earth elements are mined globally, but China dominates rare earth magnet production, controlling about 90% of global supply, CNBC reported. China also dominates refining these materials for use in electronics and aircraft, NPR reported.

Trump said that he used aircraft parts to leverage his negotiations with China. “200 of their planes were unable to fly because we were not giving them Boeing parts purposely because they weren’t giving us magnets,” he said.

The President warned the rest of the world that he’d take similar action if other countries don’t remove “digital taxes, legislation, rules, or regulations” on American tech.

“I will stand up to Countries that attack our incredible American Tech Companies,” he wrote on Truth Social . “Digital Taxes, Digital Services Legislation, and Digital Markets Regulations are all designed to harm, or discriminate against, American Technology. They also, outrageously, give a complete pass to China's largest Tech Companies.”

Negotiations toward a broader trade deal between the U.S. and China are still ongoing. In June, Washington struck an agreement with the Chinese government to ease tech restrictions and pave the way for rare earth exports to resume. The restrictions threatened to cripple supply chains for automakers and other segments of the economy that depended on it as critical components.

— Joseph Zeballos-Roig contributed to this article.