On Friday, President Donald Trump warned China of a potentially “massive” hike in tariffs and other economic measures, following China’s recent announcement of new trade restrictions on vital rare earth materials and related technologies.

In a striking post on Truth Social, Trump asserted that China has become “very hostile” on trade issues. He mentioned, “I was supposed to meet President Xi in two weeks at APEC in South Korea, but now it appears unnecessary.”

That meeting was seen by many as when the leaders of the world’s two largest economies would potentially announce a full-fledged trade deal.

A spokesperson for the Chinese Embassy in Washington, D.C., did not immediately respond to a request for comment on Trump’s post.

Following the president’s statement, U.S. stocks plummeted to their lowest point for the session. The S&P 500 dropped by nearly 1% after previously showing positive numbers, and the Nasdaq, home to many tech companies with operations in China, fell approximately 1.2%.

On Thursday, China announced a series of new limits on the trade of rare earths and technologies related to them.

The new rules mandate that foreign businesses receive special authorization to export products containing even minimal amounts of rare earth elements sourced from China. These key minerals play a role in numerous items, ranging from jet engines and radar systems to electric vehicles and consumer technology such as laptops and phones.

The U.S. and China have conducted over three rounds of trade discussions this year, with topics like rare earths, TikTok, and tariffs being addressed. Following earlier discussions in Geneva, it was noted by the administration that China intended to relax some of the rare earth export limitations.

Yet, months later, both parties reconvened in London, unveiling a further agreement on the matter. Subsequently, the U.S. anticipated that the issue would be “resolved” after these discussions.

U.S. officials plan to meet with their Chinese counterparts for further talks in November, where rare earths will likely again take center stage.