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

President Donald Trump held a long-awaited phone call Thursday with China’s Xi Jinping, a person familiar with the matter said, as the two leaders tussle over trade policy.

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.