WASHINGTON — In comments that are likely to create fresh tensions with the United States’ closest European allies, President-elect Donald J. Trump described NATO as “obsolete” in an interview published on Sunday and said other European nations would probably follow Britain’s lead by leaving the European Union.

Mr. Trump has made similar comments before. But the fact that he made them in a joint interview with two European publications — The Times of London and Bild, a German newspaper — and did so days before assuming the presidency alarmed European diplomats.

“I took such heat when I said NATO was obsolete,” Mr. Trump said. “It’s obsolete because it wasn’t taking care of terror. I took a lot of heat for two days. And then they started saying, ‘Trump is right.’”

Mr. Trump also said that Britain’s decision to leave the European Union would “end up being a great thing” and predicted that other countries would follow. “People, countries want their own identity, and the U.K. wanted its own identity,” he said.