The former president on why those waiting for Trump to disclose the existence of aliens are sure to be disappointed, and insisting first contact "hasn't happened yet."

The US has published transcripts, video clips and audio recordings about unidentified flying objects, also called unidentified anomalous phenomena.

The U.S. government has released a slew of never-before-seen files about UFOs.

Donald Trump announced his administration would begin identifying and releasing UFO-related information earlier this year.