Congress is to hold the first public hearing in decades into UFO sightings next week in the latest serious attempt by the US government to establish the origins of the phenomena.
Pentagon intelligence officials will be grilled on what they know in the first session of its kind in more than half a century.
Democrat Congressman Adam Schiff, chairman of the House intelligence committee, said: "This will give the public an opportunity to hear directly from subject matter experts, and leaders in the intelligence community, on one of the greatest mysteries of our time."
He said the UFO hearing would "break the cycle of excessive secrecy and speculation with truth and transparency".
Last year, Avril Haines, the director of national intelligence who oversees President Joe Biden's daily intelligence briefing, released a much-anticipated report into UFOs.
It examined 144 instances of "unidentified aerial phenomena" since 2004, some reported by US military pilots, but could only explain one of them with confidence. The report did not rule out the potential that China or Russia had developed super-advanced technology or extraterrestrial origins. It did confirm that the sightings were not linked to clandestine US military tests.
UFO sightings have for many decades been dismissed as the preserve of conspiracy theorists and crackpots.
But the issue is being taken increasingly seriously by politicians and the Pentagon, particularly in relation to sightings by military personnel, and near training bases.
In 2017 it was revealed that the Pentagon had been running a secret UFO unit, funded with US$22 million (NZ$35 million) in "black ops money" from Congress. At the time, Luis Elizondo, the intelligence officer who ran it, told The Sunday Telegraph: "It's pretty clear this is not us [the US]."
In the wake of last year's inconclusive report, the Pentagon has now established a new team called the Airborne Object Identification and Management Synchronisation Group (AOIMSG).
The witnesses at the hearing will include the intelligence official overseeing the new task force, Ronald Moultrie, who is Biden's Under Secretary of Defence for Intelligence and Security.
Also giving evidence will be Scott Bray, the deputy director of naval intelligence.
They will be questioned by the House intelligence committee's subcommittee on counterterrorism, counterintelligence, and counterproliferation.
Congressman Andre Carson, the Democrat chairman of the subcommittee, said: "The American people expect and deserve their leaders in government and intelligence to seriously evaluate and respond to any potential national security risks, especially those we do not fully understand."
It will be the first congressional hearing on UFOs since 1969 when the "Project Blue Book" investigation into the phenomena ended.
John Kirby, the Pentagon spokesman, said it was a "very important matter" and added: "We are absolutely committed to being as transparent as we can with the American people."
He said: "We're going to try to make sure we have a better process for identifying these phenomena, analysing that information in a more proactive, coordinated way than it's been done in the past.
"And we also are doing what we need to do to mitigate any safety issues, as many of these phenomena have been sighted in training ranges and in training environments. And so, we're very much concerned about safety of flight."
He added: "It's been sort of ad hoc in the past, in terms of a pilot here and a pilot there seeing something, and the reporting procedures haven't been consistent. So, what we're trying to do with this group [AOIMSG] is get together a process here."