As I walked out from Pakse Tactical AFB headquarters at around 1700, a bright jellyfish-like object hovered above the city.

As I walked out from Pakse Tactical AFB (Royal Lao Air Force) headquarters on a misty, late afternoon, strange lights caught my eyes. I looked up to find a massive, circular, and bright void that filled a good section of the sky. This was the size of 1 football field (100+ yards). 
Its luminous lights changed colors. This unidentified object was not solid and utterly soundless. It appeared somewhat like a gigantic jellyfish; a living organism floating approximately 3500 feet above the ground. 
The event lasted a long 3 to 5 minutes.  Afterwards, this phenomenon slowly swirled toward the horizon, disappearing into the eastern sky. It was uncanny that no soul on the entire airfield had reported or even seen this extraordinary occurrence.
Witness indicates that date of incident is approximate.  Source of report provides photographic evidence of his identity.  PD