A senior U.S. official has confirmed to Fox News that the "object" shot down over Alaska on Friday entered U.S. airspace before it was detected. 

The official told Fox News the object was detected by the U.S. military while it was "over Alaska not far from the northern coast" on Thursday night.

National Security Council spokesperson John Kirby confirmed Friday afternoon during a White House press briefing that the U.S. military shot down an "object" that was flying in territorial waters over Alaska.

Kirby added that the "object" landed on frozen waters, and that "Fighter aircraft assigned to U.S. Northern Command took down the object within the last hour."

This is a developing story. Check back for updates.