A U.S. Navy spokesperson told Newsweek: "The U.S. Navy can confirm that an E-6B Mercury aircraft did operate over the North Atlantic Ocean. We operate aircraft and vessels wherever international law ...

A version of this article appears in print on July 2, 2025, Section A, Page 8 of the New York edition with the headline: Europe’s Broiling Heat Wave Prompts Scores of Alerts for Tens of Millions.