FORT WORTH, Texas -- Experts say they have an explanation for fast-moving lights in the sky, videotaped by the Mexican air force with infrared cameras.

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The lights appeared March 5. The tape made public only this week has delighted UFO fans.

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Alleged UFOs Spotted In Mexico

But it may have been just a phenomenon associated with gases in the atmosphere.

A nuclear science researcher said the bright blurs could have been caused by electrical flashes emitted spontaneously by the atmosphere.

The lights were visible only with infrared equipment. Infrared equipment can only detect heat emanating from objects; it is unable to provide an image of the objects' exact form.

The pilots sighted the objects as they conducted a routine drug-surveillance mission.

Mexican Defense Secretary Ricardo Vega Garcia said on Wednesday that the military has made no conclusions about strange lights videotaped by Air Force personnel.

Vega said he initially believed the lights came from drug trafficking planes, but then realized the lights weren't from such aircraft.

On March 5, Mexican Air Force pilots videotaped a series of brilliant objects flying at more than 11,000 feet over Campeche.

The pilots were on a routine drug-surveillance mission.

The objects appeared to accelerate rapidly and change course.

The footage of the UFOs was released to the media earlier this week.

A Mexican air force plane allegedly captured the footage while on patrol for drug traffickers. The footage was shot in March of 2004 over the Campeche region of Mexico.

The video shows several UFOs flying in a rough formation.

The pilot reportedly said the crew saw one light at first, followed by more lights. The pilot and crew saw a total of 16 lights following them.

The pilot says he was not able to get close enough to identify the alleged UFOs, but he said he has never seen anything like it.