A suspected Chinese high-altitude spy balloon was seen over a number of sensitive sites in the US, with its location and route causing speculation it could be linked to Montana's nuclear missile sites.
The balloon was first sighted over the Aleutian Islands, through Canada, and into Montana, with China later confirming ownership.
The US military has been tracking it but the White House has decided against shooting it down under advice from defence officials.
Steps have been taken to protect against sensitive information collection.
According to multiple sources, a suspected Chinese spy balloon was detected over Billings, Montana on Wednesday, having first flown over the Aleutian Islands and through Canada.
The balloon's route and location have prompted some to speculate that its movements may be in some way linked to Montana's nuclear missile sites, although this has not been confirmed by any officials.
A number of sources report that the balloon is a high-altitude one, used for spying purposes.
While the US military is continuing to track the balloon, the White House ruled out shooting it down following advice from defence officials.
Reuters reports a Pentagon official as stating, "The object has not reached out territorial airspace and at this time, we don't see it as a threat to the homeland.
" China confirmed ownership of the balloon, claiming it is a civilian airship used for research purposes that was blown off course due to strong winds.
Chinese officials have since confirmed responsibility for the balloon's presence, while US officials have declined to comment on whether they are investigating any link between the balloon and Montana's missile sites.
A defence official quoted by The Independent expressed concern that the balloon could be gathering sensitive information, while another Pentagon official noted that steps had been taken to "protect against the collection of sensitive information".
Despite these precautions, it is not clear where the balloon is currently located.