It was determined to not be a threat to national security, the official said.
What is being characterized as a small balloon was intercepted by fighter aircraft Friday morning over Utah at an altitude of 43,000 to 45,000 feet and is being allowed to continue to fly above the United States because it has been determined not to pose a national security threat said, the North American Aerospace Defense Command (NORAD) said in a statement.
A U.S. official described the balloon as being 50 feet tall and carrying a payload that is the size of a two-foot cube. It is not known what the payload might be carrying the official said.
"In close coordination with the Federal Aviation Administration (FAA), North American Aerospace Defense Command (NORAD) detected a small balloon at an altitude varying between 43,000-45,000 ft." said a NORAD statement issued Friday.
"The balloon was intercepted by NORAD fighters over Utah, who determined it was not maneuverable and did not present a threat to national security," it added.
"NORAD will continue to track and monitor the balloon," said the statement. "The FAA also determined the balloon posed no hazard to flight safety. NORAD remains in close coordination with the FAA to ensure flight safety,"
The origins of the balloon are unclear as is how it came to first be tracked by NORAD said the U.S. official.
The development comes slightly more than a year after a Chinese spy balloon was tracked across the United States before being shot down by U.S. fighters over U.S. territorial waters east of South Carolina.
That balloon measured nearly 200 feet in height, was equipped with a payload described as being the length of three school buses that carried intelligence sensors, and was capable of being maneuvered remotely.
That incident created tensions between the United States and China that have only recently improved.
NORAD subsequently made adjustments to its sensors to increase the detection of high altitude balloons flying across the United States and Canada that led to the shootdown of smaller balloons over Alaska, Canada's Yukon Territory, and Lake Huron.