He didn’t say who was interested in buying the app, just that it was “a group of very wealthy people.” But the Chinese government needs to approve any sale.

Rare earths are among the most critical raw materials on the planet, deeply embedded in the technologies that underpin modern life. Yet few people had even heard of them until the eruption of the US-China trade war thrust them into the limelight.

WASHINGTON—President Trump said he terminated trade talks with Canada over what he called an “egregious” digital-services tax on U.S. tech companies, plunging relations with America’s second-largest trading partner back into turmoil.