Timeline: What and where fighter jets have shot down unidentified aircraft

A timeline of what and where fighter jets have shot down unidentified aircraft so far this month: 

February 4

Shot down: Off Surfside Beach, South Carolina

A US defence official said the aircraft was a spy balloon and that China had intended to use it on sensitive military sites.

However, China insisted the balloon was used for meteorological and other scientific research and had been blown off course.

February 10

Shot down: Off Deadhorse, Alaska

A second object, described as being “about the size of a small car”, was spotted by the North American Aerospace Defense Command near Alaska