President Donald Trump has threatened to pull out of an expected meeting with President Xi Jinping of China after Beijing tightened its rules for exports of rare earths.
In a post on social media, Trump said he now saw "no reason" to meet with President Xi later this month, accusing China of "becoming very hostile" and trying to hold the world "captive".
He also threatened a "massive" increase in tariffs on Chinese goods, raising fears about a renewal of trade tensions between the two economic giants.
Financial markets dropped in the wake of the remarks, with the S&P 500 down roughly 1.4% in late morning trade in New York.
As well as tightening rules for exports of rare earths, China has opened a monopoly investigation into the US tech firm Qualcomm that could stall its acquisition of another chipmaker.
