Pentagon's seventh UFO file release reveals black triangles racing at 1,800mph over secret US military bases

Officials still cannot say whether the silent craft came from a foreign power, after three separate sightings over the past year. Witnesses said the 9ft objects hovered at 200 to 300 feet with no sound, lights or exhaust. Thermal scans showed a steady heat signal unlike any plane or drone. Some officials warned America may be years away from matching the technology.

A redacted Roswell witness described 4ft alien bodies beside an egg-shaped craft in a guarded hangar.

White House spokesperson Anna Kelly said: 'The American people asked, and President Trump delivered.'

Pentagon spokesman Sean Parnell said more files will follow on a rolling basis.