PHOENIX -- Former Arizona Gov. Fife Symington joined other top officials in Washington, D.C. on Monday to speak out about unidentified flying objects.

VIDEO: Symington Explains What He Saw

After sighting what he called a UFO in 1997, Symington held a news conference where his chief-of-staff was dressed as an alien. But Symington was all business Monday as he moderated a discussion at the National Press Club of UFO sightings.

ONLINE: The Phoenix Lights

Symington feels strongly that humans may not be alone in the universe.

"The universe is such a big place, I just think that you have to be open to that possibility," he said.

It was during his second term as governor that Symington saw a delta-shaped object split the sky over Squaw Peak.

The Phoenix Lights, sometimes referred to as "the Lights over Phoenix," were seen March 13, 1997, when thousands of people reported seeing the phenomena. There were two distinct events -- a triangular formation of lights seen to pass over Arizona and a series of stationary lights seen in the Phoenix area.

The U.S. Air Force said the lights were caused by flares dropped by a-10 Warthog aircraft in training exercises over the Barry Goldwater Air force Range.

Symington and many high-ranking military, aviation and government officials never bought into that explanation.

Symington said he saw a large triangular "craft of unknown origin" with lights. He said it could not have been flares because it was too symmetrical.

In an interview last March with The Daily Courier in Prescott, Symington responded to the military claims that the lights were caused by flares. "I'm a pilot and I know just about every machine that flies. It was bigger than anything that I've ever seen. It remains a great mystery. Other people saw it, responsible people. I don't know why people would ridicule it."

Frances Barwood, a Phoenix city councilwoman, launched an investigation into the event and interviewed more than 700 witnesses. She said, "The government never interviewed even one."

While Symington spoofed the incident at the 1997 news conference, he now wants to set the record straight.

He says Arizona was "on the brink of hysteria" about the UFO sighting at the time and the frenzy was building.

"I wanted people to lighten up and calm down, so I introduced a little levity. But I never felt that the overall situation was a matter of ridicule," he said, adding that the incident remains unsolved and deserves an official investigation.

Among those joining Symington in Monday's panel discussion were several pilots, former Belgian Deputy Air Force Chief of Staff Gen. Wilfried De Brouwer, retired Air France Capt. Jean-Claude Duboc and former United Kingdom Defense Minister Nick Pope.