Jeremy Herb

Three retired military veterans are testifying Wednesday at a House hearing on unidentified anomalous phenomena – commonly known as UFOs – warning that the sightings are a national security problem and that the government has been too secretive about them.

The US government is tracking more than 650 potential cases of so-called "unidentified aerial phenomena," commonly known as UFOs, according to the director of the office created last year to focus on the sightings.