One of the pilots whose encounter with a mysterious - and still unexplained - object off the coast of the US in 2004 says whatever it was, it committed an "act of war".
In November 2004, anomalies had been detected on radar off the coast of California. Commander David Fravor, then a US Navy pilot, was dispatched to investigate - later describing what he saw as "like nothing I've ever seen" - a 14m-long Tic Tac-shaped object able to turn on a dime and make itself invisible to radar.
He was followed by other pilots who managed to catch it on video. Clips were leaked in 2017 by a UFO research group founded by punk singer Tom DeLonge of Blink 182, and formally declassified in 2020 by the Pentagon.
Fravor recently appeared on a podcast hosted by MIT research scientist Lex Fridman, who called him "one of the most credible witnesses" in the history of UFO research.
He said the encounter lasted several minutes, and was reacting to what they were doing.
"This is not like, 'we saw it and it was gone', or 'I saw lights in the sky and it's gone' - we watched this thing on a crystal clear day with four trained observers."
Fravor said he tried to get close to it, but once he got within a few hundred metres it accelerated so quickly, it was gone in just half-a-second.
"I remember telling the guy in my back seat, 'Dude, I dunno about you but I'm pretty weirded out.'"
Once he landed, Fravor mentioned the object to another pilot, Chad Underwood, who was about to take off.
Underwood found the UFO, aimed his radar at it - and got jammed.
"He's telling the radar, 'Stare down the line of sight, whatever is there I want you to grab it and build a trace file on it,' which will tell you where it is, how fast it is and the direction that it's going," said Fravor.
"The radar is smart enough that when the signal comes back if it's been messed with, it will tell you - it will give you indications that it's being jammed.... It's being jammed into about every mode you can see... You can tell it's being jammed.
"When you actively jam another platform, that's technically an act of war."
He said aside from that, the object reacted exactly as he would have if he was piloting it - except it could do things no known human technology can.
"I don't like to get into little green men but I don't think we've developed it... I think you can hide things for a while. This is a giant leap in technology."
The origin of the object remains unknown. Some US Senators have suggested it could be Russian or Chinese technology.
"We have things flying over our military bases and places where we are conducting military exercises, and we don't know what it is and it isn't ours, so that's a legitimate question to ask," said Republican Senator Marco Rubio, a member of the committee.
"Frankly, if it's something from outside this planet, that might actually be better than the fact that we've seen some sort of technological leap on behalf of the Chinese or the Russians or some other adversary."
An astrophysicist who used to work for the Pentagon's secret UFO division claimed in July it was the US military itself that had "off-world vehicles not made on this Earth".