A “high-altitude object” was shot down over Alaska earlier on Friday, the White House has said.
Spokesman John Kirby said the unmanned object was “the size of a small car” and was over a sparsely populated area at the time.
President Joe Biden took the decision to shoot down the object, which was of unknown origin, Mr Kirby said.
It comes after the US shot down a Chinese balloon over its territorial waters last Saturday.
Speaking at the White House on Friday, Mr Kirby explained that the object over Alaska was travelling at 40,000ft (12,000m) and posed a “reasonable threat” to civilian aircraft.
He said the object had fallen into US waters that are currently frozen, adding that its debris field was “much, much smaller” than the balloon shot down last week off the coast of South Carolina.
“We do not know who owns it, whether it’s state owned or corporate owned or privately owned,” Mr Kirby said.
He said a fighter jet had approached the object and assessed there was nobody onboard, and this information was available to Mr Biden when he made his decision.
Pentagon press secretary Brigadier General Pat Ryder confirmed that an F-22 jet shot down the object – which was moving at an unknown speed – with a sidewinder missile at 13:45 EST (18:45 GMT).
Mr Ryder said a significant amount of debris had been recovered so far.
It was being loaded onto vessels and taken to “labs for subsequent analysis,” he said, which “will prove helpful to our further understanding of this balloon and its surveillance capabilities”.
Officials have not yet determined whether the object was involved in surveillance, and Mr Kirby corrected a reporter who referred to it as a balloon.
He did not specify the exact location where the object was shot down, but the Federal Aviation Administration said it had closed airspace in the area of Deadhorse, in northern Alaska. (BBC)