evidence: China acknowledged Friday that a high-altitude balloon spotted this week over the U.S. does in fact belong to Beijing, but it referred to the airship as a civilian device "used for scientific research such as meteorology." A senior defense official told CBS News on Thursday that the Defense Department was "confident" that it was, in fact, a Chinese surveillance balloon. [...] After earlier sightings over Montana, the balloon moved along Friday to cross "the middle of the country," according to a U.S. official. A Chinese balloon has never been over the middle of the country before. The only other time a Chinese balloon has flown over the continental U.S. was during a brief overflight of Florida. There have been overflights of Hawaii and Guam. In previous instances, the Chinese have been able to recover the balloon. Although it can maneuver, it will still travel in the direction it is carried by the jet stream. [...] Montana Gov. Greg Gianforte said Thursday in a statement that he had "received an informational briefing" Wednesday "on the situation involving a suspected Chinese spy balloon flying over Montana," and added that he was "deeply troubled by the constant stream of alarming developments for our national security."