British Prime Minister Keir Starmer said Britain is working with allies on a viable plan to open the Strait of Hormuz, but he offered few specifics and no timetable for when any collective action might take place.

Mr. Starmer was responding to warnings from U.S. President Donald Trump who said on Sunday that if NATO allies didn’t help open the strait, “it will be very bad for the future of NATO.”

In a press conference on Monday, Mr. Starmer said no decision had been made about whether Britain would join an effort to patrol the strait, and he made it clear that it would not be a NATO mission.

“It’s a discussion. We’re not at the point of decisions yet. It’s obviously a difficult question, that goes without saying, in relation to how you safeguard maritime traffic,” he told reporters.