The U.S. is tracking a suspected Chinese surveillance balloon that has been spotted flying over sensitive sites.
Defense officials said the balloon had been watched since it entered U.S. airspace by several methods, including crewed aircraft. It has most recently been tracked crossing Montana, home to one of the country's three nuclear missile silo fields, at Malmstrom Air Force Base.
U.S. Secretary of State Antony Blinken is expected to travel to China next week for a visit agreed to in November by Biden and Chinese President Xi Jinping. It was not clear how the discovery of the spy balloon might affect those plans.