US and RAF fighter jets were scrambled to a massive UFO covered with flashing lights above the Mediterranean, according to top secret files.
A US spy plane reported encountering a 130ft flying object with 20 flashing lights near Cyprus.
Two US Navy F-14 fighters and an RAF Phantom were sent to aid the US Air Force RC-135.
The American spy plane crew said the UFO turned away and flew off in the direction of the African coast.
Britain and the US launched investigations into the close encounter – but it has never been explained.
The shocking 90-minute incident was part of a stash of confidential UFO files released by the British Ministry of Defence and reported by journalist and transparency campaigner Dr David Clarke, on his blog.
It happened on October 19, 1982 – but has never been publicly known until now.
Last month, the same set of British X-files revealed the RAF watched a UFO on its radar for seven hours – but were told be commanders not to engage it.
Interestingly, film, tapes and transcripts of the US crew’s distress call have not been released.
The RC-135 was monitoring Soviet military activity it encountered the “big object”.
It was picked up on the plane’s advanced radar as it approached from the south.
The unidentified flying object circled around the spy plane, according to its crew.
The RAF Troodos radar base on Cyprus as “larger than [an] RC-135”.
RC-135 are 136ft long and have a wingspan of 130ft.
The results of the US-UK probe into the incident are not included in the file, released to the National Archive in Kew, London.
But one official writes: “We have a strong suspicion that the ‘UFO’ was a mirage effect from lights on the coast of Israel or Lebanon.”
However, it is unclear how the crew could be so confused for 90 minutes or why they would think the UFO was flying around them.