The U.S. military is tracking a high-altitude balloon over the Western United States, two U.S. officials confirmed to Fox News on Friday. 

It was spotted by U.S. military aircraft and determined to not be a threat. 

The origin of this balloon and its purpose are not yet known, the two officials said.

The balloon is drifting east in the jet stream. 

A year ago, a Chinese spy balloon was discovered and shot down after it flew over the U.S. for several days. 

The suspected Chinese spy balloon drifts to the ocean after being shot down off the coast in Surfside Beach, South Carolina, U.S. February 4, 2023.  (Randall Hill/Reuters)

The Pentagon said in June that while the Chinese balloon had “intelligence collection capabilities,” it didn’t collect any data before it was shot down. 

“We also took steps to mitigate the potential efforts of that balloon,” Pentagon press secretary Brig. Gen. Pat Ryder said in June. 

Intelligence agencies have concluded that the spy balloon was used for spying, not weather-related issues as China had claimed. 

FILE PHOTO: A jet flies by a suspected Chinese spy balloon as it floats off the coast in Surfside Beach, South Carolina, U.S. February 4, 2023.  REUTERS/Randall Hill/File Photo (Reuters)

Information captured by the spy balloon is not believed to have been successfully sent back to Beijing. It is unclear why the spy mission seemed to fail, but officials said intelligence agencies used countermeasures to prevent data collection. 

The Chinese spy balloon flew from Alaska to the East Coast, where it was shot down by the military over the Atlantic Ocean on Feb. 4. 

This is a developing story.

Fox News’ Bradford Betz contributed to this report.