The U.S. Federal Aviation Administration (FAA) said in an update late on Saturday that it has closed some airspace in Montana for Defense Department activities.

The temporary flight restriction from the FAA was issued for flights in an area about 50 by 50 nautical miles above Havre, Montana, near the Canadian border. The notice reclassified the area as “national defense airspace.”

The FAA declined to say if it was in relation to another balloon or another object. The FAA issued similar actions in response to a suspected Chinese spy balloon that crossed the continental United States from Montana to South Carolina and was shot down earlier this month.

Reuters contributed to this article.