"I'm not going to categorise them as balloons. We're calling them objects for a reason," he said.
"What we are seeing is very, very small objects that produce a very, very low radar cross-section," he added.
Speculation as to what the objects may be has intensified in recent days.
"I will let the intel community and the counterintelligence community figure that out," Gen VanHerck said when asked if it was possible the objects are aliens or extra-terrestrials.
"I haven't ruled out anything at this point." บาคาร่า777
A suspected Chinese spy balloon was downed off the coast of South Carolina on 4 February after hovering for days over the US. Officials said it originated in China and had been used to monitor sensitive sites.