Story By:  Ana Marjanovic, Sub-Editor: Michael Leidig, Agency:  Newsflash

A mysterious flying saucer astonished witnesses when it seemed to hover over a city after suddenly appearing in western China.

The perfect black ring can be seen hanging in the air as locals film and observe it floating in the sky.

In one piece of video footage – filmed in Chengdu, the sub-provincial capital of Sichuan province – excited children run laughing towards the ring.

But officials were quick to quash rumours that it was anything mystical or extra-terrestrial by explaining it had been caused by an explosion.

A small electricity substation had apparently exploded causing a black smoke ring that then spiralled upwards into the sky.

Many people had spotted the black circle and photographed it to post on social media where it caused intense speculation as to how it had been created.

The media that then went to investigate were told by locals that there was an explosion at a substation with electricity outages, and when they contact the public to check, it was confirmed that this was indeed the case.

Apparently, it had been a hot day, many people have been using air-conditioning units and the substation had simply overheated and then exploded.