The strange display was captured by the live stream camera which constantly monitors the Popocatepetl volcano in Mexico to watch for signs of eruption.
It was seen on the webcamsdemexico website on June 19 at 12.12am local time, by UFO hunter Scott C Waring, who was astonished.
In the short clip there are a series of bright orbs that file in and out of camera shot.
Mr Waring blogged on his website ufosightingsdaily.com: “I have been watching this volcano for over five years and have caught a few UFOs here and there, but this is the most extraordinary video from the live Mexico volcano cam that I have ever seen.
“I have seen such a UFO before on this cam, but it was alone.
“Here we see over ten of them flying around.
“I believe the only reason these UFOs can be seen is that at this moment, the camera had on its infrared mode, which means it can see things the human eye cannot…basically its night vision on steroids.”
But Scott Brando, a forensic UFO investigator, who runs the hoax-busting website ufoofinterest.org said the “orbs” were nothing more than dust or insects.
Mr Brando pointed to earlier footage taken from the webcam, showing the orbs when it was identified as dust and other debris being expelled from the volcano.
He told Express.co.uk: “It’s a night-vision/infrared webcam, so it’s more sensitive to small light source or bugs crossing the camera lens.
“For example dust by eruption causes the same effect.
“Dust near the camera lens is brighter, the furthest debris is less bright.”