An ex-US Navy pilot says he saw unidentified flying objects every day for at least two years - and he believes they could be a threat to national security.
Former Navy Lieutenant Ryan Graves told 60 Minutes he saw unidentified vessels in restricted airspace near Virginia Beach in the state of Virginia every day between 2015 and 2017.
He's one of several current and former military members who have spoken publicly about seeing what the Pentagon now calls unidentified aerial phenomena.
Graves says the objects are worrying.
"If these were tactical jets from another country that were hanging out up there, it would be a massive issue," Graves said. "But because it looks slightly different, we're not willing to actually look at the problem in the face. We're happy to just ignore the fact that these are out there, watching us every day."
He says himself and other pilots theorised the objects could be secret US technology, technological devices used by the enemy - or something else entirely.
"I don't know. I don't know what it is, frankly."
Last year it was revealed the US Navy has been investigating unidentified aerial phenomena, and videos shot by experienced pilots showing mysterious objects pulling off seemingly impossible manoeuvres have also made headlines.
In January, the CIA declassified a trove of documents about UFOs and the paranormal, including reports looking into Nazi flying saucers, captured aliens and mysterious unexplained explosions.
