Gateway Arch UFO
Unidentified flying objects - Representational image VCG/Getty

UFOs seem to be the trending topic these days, especially after the latest revelations about a super-secret project reportedly being undertaken by the Pentagon. Residents of Mexico City were treated to a UFO sighting when they witnessed glowing white balls floating in the sky.

The sighting has been captured on video, which shows five white balloon-like objects flying randomly across the blue sky. The unexplained incident took place earlier this month but the video has emerged online only now. An eyewitness reportedly told a local media outlet that the glowing balls hovered in the sky for a good 20 minutes before disappearing.

"There were five balls and they were moving, now they are moving around together. I have been here for 20 minutes and they are still there," the spectator said at the time, according to the Daily Mail. "They were white points seen in the sky that were moving and were making a triangle," added another.

While many believed these were UFOs, some dismissed the notion that the objects were alien crafts. "They are white balloons, maybe they are bright because they are covered in silver which is very common at Christmas. If they were aliens, they would have destroyed the planet," an eyewitness said.

There are a few who believe the flying white balls could also have been floating balloons at a high altitude and were glowing due to the sun's reflection, while others think the objects could have been weather balloons.

The sighting has garnered more interest among internet users after recent revelations were made about the American military reportedly running a secret Advanced Aerospace Threat Identification Program. This government programme has been set up to investigate the possibility of the existence of aliens who might be keeping a tab on earthlings through their unidentified flying objects, according to reports.

To add more fuel to the theory that aliens exist, former US Navy fighter pilot David Fravor claimed recently that he saw a 40-foot long oval-shaped wingless object flying randomly in the sky at an altitude of over 80,000 feet before it drastically dropped to around 20,000 feet. Fravor said that the incident took place in 2004 and that he does not believe the craft was made by humans.

"It looked like a flying Tic Tac with incredible capabilities. I'd say I doubt it was something we developed – Earthlings, people of this planet," he told the Boston Herald.