Officials said it appeared to be able to propel itself using winds and possibly a propulsion mechanism.
After this, on Friday, American fighter jets shot down another object near northern Alaska. Officials said it was much smaller than the Chinese balloon and had no propulsion or control system.
On Saturday, a US F-22 jet acting on orders from the US and Canada shot down a “high-altitude aerial object” over Canada’s far-northwest Yukon Territory, saying it posed a threat to civilian flight Is. Canada described it as cylindrical and about the size of a Volkswagen Beetle.
On Sunday, Biden ordered US warplanes to drop another unidentified object over Lake Huron. The object was described as an octagonal structure with wires dangling from it.
Officials said it also posed a danger to civil aviation as it flew at about 20,000 feet (6,000 m).
The Pentagon said that none of the four objects appeared to be armed or at any risk of attack.
Officials would not comment on the origin or function of the three objects that followed the Chinese balloon. So far only the balloon has been attributed to Beijing.