President Donald Trump said the U.S. has reached a trade deal with the United Kingdom, the first trade pact since he paused reciprocal tariffs and began negotiating with countries to lower trade barriers.

Courting Trump: A trade deal would provide Prime Minister Keir Starmer of Britain a much-needed political victory, as well as vindication of his strategy of assiduously cultivating a relationship with Mr. Trump. Mr. Trump’s announcement on social media seemed to catch even senior British officials off guard, after weeks of negotiations.