A former NASA astronaut believes humans are not alone in the universe and "there's something out there" after reading the conclusions of the US Government's highly-anticipated UFO report.

The nine-page dossier confirmed flying objects may be a national security threat but also couldn’t rule out extraterrestrial life.

Former NASA astronaut Bill Nelson believes humans "are not alone” after reading a classified version of the report.

He told CNN Monday: "I’ve seen the classified report. It says basically what we thought.

"We don’t know the answer to what those Navy pilots saw, they know that they saw something, they tracked it, they locked their radar onto it, they followed it, it would suddenly move quickly from one location to another."

The former Florida Senator thinks another life exists in the galaxy, The New York Post reports.

Nelson, who is now NASA administrator, said: "My feeling is that there is clearly something there. It may not be extraterrestrial but if it is a technology that some of our adversaries have, then we better be concerned.”

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