A report on US TV programme '60 Minutes' delved into sightings of UFOs.

UFOs are also referred to as UAP, aka Unidentified Aerial Phenomena. In the report, a number of military pilots spoke about the strange sightings.

In an interview with co-host Bill Whitaker, Lt. Ryan Graves said that he saw UAPs almost daily for two years.

He said that the unidentified objects could be U.S. technology still in development, secret spy technology from another country, or "something otherworldly."

He noted that if they're identified as tactical jets, or something Russian or Chinese, the military take them seriously. However UFOs or UAP get largely ignored and go uninvestigated.

Naval Aviators David Fravor and Alex Dietrich referenced a particular 2004 incident in which they saw a UAP, that was also captured by radio and photos.

"It was unidenitified and that's why it was so unsettling to us, because we weren't expecting it, because we couldn't classify it," said Dietrich.

Fravor explained of the incident: "So, as we're looking at this, her back-seater says, 'Hey, Skipper, do you…?'

"And about the time that got out, I said, 'Do you see that down there?' And we saw this little white tic-tac object and it's moving right above the white water area."

One party approached the object while the other circled. After mirroring their moves, circling with them ("it was aware we were there"), the object disappeared, taking off in another direction.

"We have nothing that's that fast and just starts climbing at will," Fravor also noted.

They reacquired the target 60 miles away, an incredible distance covered within seconds. They got flare footage of the UFO before it disappeared altogether.

Dietrich said she felt "vulnerable" and "confused" by the sighting. The pilots were ridiculed by their team for what they'd seen.

Watch the '60 Minutes' report here.