A former Pentagon official who led a secret government programme to combat UFO attacks says he believes aliens have visited Earth.
Luis Elizondo previously ran the Advanced Aerospace Threat Identification Programme which, leaked records show, investigated reports of clashes with unidentified aircraft, MailOnline reported.
The former chief of the $22 million project says he thinks "we may not be alone", based on numerous reports he read on encounters with the flying craft.
Many reportedly displayed out of this world capabilities in terms of both speed and manoeuvring.
News of the off-the-books Department of Defense (DoD) programme emerged over the weekend.
It sought to identify what had been seen, either through tools or eyewitness reports, and then "ascertain and determine if that information is a potential threat to national security".
Elizondo resigned from the DoD in October in protest over what he has termed excessive secrecy and internal opposition to the project, whose funding was cut in 2012.
He has now said there is evidence which leads him to believe alien aircraft have visited the planet.
Speaking to CNN, he said: "My personal belief is that there is very compelling evidence that we may not be alone.
"These aircraft - we'll call them aircraft - are displaying characteristics that are not currently within the US inventory nor in any foreign inventory that we are aware of.
"Things that don't have any obvious flight services, any obvious forms of propulsion, and maneuvering in ways that include extreme maneuverability beyond, I would submit, the healthy G-forces of a human or anything biological."
Among the sightings were reports from pilots of two US Navy Super Hornet fighters who spotted a UFO on a training mission.
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