US President Joe Biden ordered a fighter jet to shoot down an unidentified “high-altitude object” off Alaska on Friday, the White House says.
Spokesman John Kirby said the unmanned object was “the size of a small car” and posed a “reasonable threat” to civilian aviation.
The object’s purpose and origin was unclear, Mr Kirby said.
It comes a week after the American military destroyed a Chinese balloon over US territorial waters.
Speaking at the White House on Friday, Mr Kirby said the debris field of the object shot down on Friday was “much, much smaller” than the balloon shot down last Saturday off the coast of South Carolina.
He said that the object was flying at 12,000m over the northern coast of Alaska.
It had already flown across Alaska at a speed of 20 to 64km/h and was out over the sea travelling towards the North Pole, when it was shot down.
Helicopters and transport aircraft have been deployed to collect debris from the frozen waters of the Beaufort Sea.
“We do not know who owns it, whether it’s state owned or corporate owned or privately owned,” Mr Kirby said.
The object was first spotted on Thursday night, though officials did not specify a time.