An alleged spy balloon spotted over the US is a Chinese "civilian aircraft" that had deviated from its planned route, China says.
US defense officials said they believe the balloon, seen over sensitive areas in recent days, was actually a "high-altitude surveillance" device.
But in a statement, China's foreign ministry said it was used for "mainly meteorological" purposes.
China "regrets the inadvertent entry" of the balloon into US airspace, it added.
The object flew over Alaska's Aleutian Islands and across Canada before appearing over the Montana town of Billings on Wednesday, US officials said.
Montana is home to some of the US's nuclear missile silos.
The United States decided not to shoot down the balloon because of the danger posed by falling debris and the limited use of any intelligence the device could gather, the U.S. defense official said.
However, the government prepared fighter jets in case the facility had to be brought down. US media earlier reported that the balloon was the size of three buses, according to another official.