The first public congressional hearing into UFO sightings in the US in over 50 years ended with few answers about the unexplained phenomenon.

Two top military officials tasked with probing the sightings said that most can ultimately be identified.

But they said a number of events have defied all attempts at explanation.

The sightings recorded by the military include 11 "near-misses" with US aircraft.

Some Unexplained Aerial Phenomena (UAPs) - as the military terms UFOs - seem to have been moving without any discernible means of propulsion.

What happened at the hearing?

During the hearing at the House Intelligence Counterterrorism, Counterintelligence, and Counterproliferation Subcommittee, top Pentagon intelligence official Ronald Moultrie said that through "rigorous" analysis, most - but not all - UAPs can be identified.

"Any object we encounter can likely be isolated, characterised, identified and, if necessary, mitigated," Mr Moultrie said.

A small number of incidents, however, still have no explanation. In one such incident in 2004, fighter pilots operating from an aircraft carrier in the Pacific encountered an object that seemed to have descended tens of thousands of feet before stopping and hovering.

In another incident, shown publicly for the first time on Tuesday, an object can be seen on camera flying past a US Navy fighter jet. The object remains unexplained.

"There are a small handful [of events] in which there are flight characteristics or signature management that we can't explain with the data we have available," said Scott Bray, the deputy director of naval intelligence. "Those are obviously the ones that are of most interest to us."

Mr Bray also sought to dispel the notion that UAPs might be extraterrestrial aliens, noting that no organic or inorganic material or unexplainable wreckage has ever been recovered, and no attempts have been made at communicating with the objects.

"We have detected no eliminations within the UAP task force that...would suggest it's anything non-terrestrial in origin," he said.

A national security threat?

Lawmakers at the hearing expressed concern that any unexplained aerial phenomenon might be a threat to national security.

Rick Crawford, an Arkansas Republican, said that a failure to identify potential threats was "tantamount to intelligence failure that we certainly want to avoid".

"It's not about finding alien spacecraft," he added.

In the cases of objects with unexplainable propulsion, Mr Bray said that the US is "not aware" of any potential adversaries with such technologies.

Following the public hearing, the committee closed its doors for a private classified session with lawmakers.

How did we get here?

Public fascination with flying saucers, glowing lights and otherworldly aircrafts has been ongoing for generations.

The last public hearings into the issue began in 1966, when Republican congressman - and future president - Gerald Ford convened a pair of hearings to discuss a UFO sightings following one in Michigan that was observed by over 40 people, including a dozen policemen.

The Air Force officials attributed the incident to "swamp gas", leadi

The Air Force officials attributed the incident to "swamp gas", leading Ford to deride their description as "flippant" .

In 1969, an Air Force investigation into UFOs called Project Blue Book closed after determining that no flying object had ever been confirmed or deemed a threat to US national security.

Blast forward to 2017, when US media reported on the Pentagon's secretive efforts to probe testimony from pilots and other US military members who had reported seeing strange objects in the sky.

The reports included footage of the UFOs, and descriptions of how they seemed to fly in unexpected ways, including hovering in place during high winds and changing elevation rapidly.

Pilots described seeing them on an almost "daily basis" outside military bases, and one whistleblower described how UAPs had interfered with US nuclear weapons facilities, even forcing some offline.

In 2020, a Covid relief bill signed by Donald Trump included a provision requiring US intelligence agencies to deliver an unclassified report on UAPs within 180 days.

In June 2021, the US Director of National Intelligence released a report saying it had no explanation for dozens of unidentified flying objects related to 144 incidents dating back to 2004. Only one could be easily explained as a deflating balloon, while the others were labelled "largely inconclusive".

"Most of the UAP reported probably do represent physical objects," the report stated, adding that 80 of them were detected on multiple advanced military sensors and radar systems.

The June 2021 report failed to reach any conclusive answers in regards to what the objects are, or how they function. It called for expanded investigation and better data collection, given the stigma government workers may have against their describing unexplained encounters.

Last December, Democrats succeeded in including a stronger disclosure requirement in the annual National Defense Authorization Act signed by Joe Biden.

The law requires the military to establish a permanent office on UAP research - now called the Airborne Object Identification and Management Synchronization Group.