San Diego residents were left baffled by a set of more than ten lights floating in the night sky, sparking speculation of extra-terrestrial activity.
Footage filmed last night (August 29) above the California city shows the group of yellow orbs floating high in the sky.
The filmer, Daniel Burns, writes: "As I looked from La Mesa towards the San Diego downtown skyline I noticed some orange glowing lights in the sky.
"One by one they got brighter and more joined in. Then 2 minutes later they went out. A second set was lit not too long after."
The strange sighting caused speculation over whether it was a visit by guests from another planet.
One Twitter user wrote: "Extraterrestrial lights randomly appearing in the air of Pacific Beach, San Diego. What are they?"
The US Navy later confirmed the UFOs were in fact flare lights from an aircraft training exercise.