High-level delegations from the United States and China are meeting in London to try and shore up a fragile truce in a trade dispute that has roiled the global economy

Mr. Trump said in a post on Truth Social that his call with Xi Jinping, China’s top leader, had focused entirely on the trade relationship between the nations, which has soured in recent months in a dispute over the export of critical minerals used in an array of industries.

The rare leader-to-leader call confronted weeks of brewing trade tensions and a battle over critical minerals but left key issues to further talks.