The United States has shot down an unknown object flying in US airspace off the coast of Alaska on orders from President Joe Biden, White House officials say.
The object, which was the size of a small car, was flying at about 40,000 feet and posed a "reasonable threat" to the safety of civilian flights, John Kirby, White House National Security Council spokesman said.
Commercial airliners and private jets can fly as high as 45,000 feet.
Many details were unknown, but the US expected to recover the object after it landed in US territorial waters, he said.
It was unclear where the object came from or who owned it, Mr Kirby said.
Officials also couldn't say if there was any surveillance equipment on it.
It was the second time in a week the US had shot down some type of flying object over its airspace.
Last Saturday, fighter jets destroyed a suspected Chinese spy balloon off the coast of South Carolina.
'Vigilant about our airspace'
Mr Kirby was careful not to classify the new object as a balloon.
He said the knowledge about the unidentified object and its track first came to US attention on Thursday night.
The Pentagon declined to provide a more precise description of the object, only saying that US pilots who flew up to observe it determined it didn't appear to be manned.
Officials said the object was far smaller than the balloon shot down last week, did not appear to be manoeuvrable and was travelling at a much lower altitude.
Mr Kirby maintained that Mr Biden, on the advice of the Pentagon, believed it posed enough of a concern to shoot it out of the sky — primarily because of the potential risk to civilian aircraft.
"We're going to remain vigilant about our airspace," Mr Kirby said.
"The president takes his obligations to protect our national security interests as paramount."
The president was briefed on the presence of the object Thursday evening after two fighter jets intercepted it.
Pentagon press secretary Brigadier General Pat Ryder said an F-22 fighter aircraft based at Joint Base Elmendorf-Richardson shot down the object using the same type of missile used to take down the balloon nearly a week ago.
Ahead of the shoot-down, the Federal Aviation Administration restricted flights over a roughly 25-square kilometre area within US airspace off Alaska's Bullen Point, the site of a disused US Air Force radar station on the Beaufort Sea about 160 kilometres from the Canadian border.
The object flew over one of the most desolate places in the United States, the northern-most region of Alaska known as North Slope, making it unlikely that there were sightings of it from the ground.
Canadian Prime Minister Justin Trudeau tweeted that he had been briefed and supported the decision.
"Our military and intelligence services will always work together," he said.
Defence and military officials were criticised for the decision to delay shooting down the suspected Chinese espionage balloon until a week after it initially entered US airspace over Alaska.
The twin downings in such close succession reflect heightened concerns over China's surveillance program and public pressure on Mr Biden to take a tough stand against it.
ABC/wires
