The US military has confirmed it spent more than 100 million dollars investigating UFO reports, from a secret office at the Pentagon.

The Advanced Aerospace Threat Identification Programme had a budget of 22 million US dollars a year.

The program was founded by retired senator Harry Reid and took place as recently as from 2007 until 2012 when it was reportedly closed.

Most of the money went to a company now linked to a prominent senator at the time.

The military isn't saying if it found any aliens.