A Chinese airport was closed after this mysterious object was spotted in the sky.

Arcing over Zhejiang's provincial capital Hangzhou, the UFO appeared to glow with an eerie white light and left a bright trail in its wake.

Xiaoshan Airport was closed after the UFO was detected at around 9 pm and dozens of flights had to be diverted.

Stunned witnesses reported seeing a comet-like fireball in the sky and a number of local residents took photos of the strange ball of light.

A local bus driver, giving his name only as Yu, said he had seen a strange glowing object in the sky late on Wednesday afternoon. 'The thing suddenly ran westwards fast, like it was escaping from something,' he said.

Inbound flights were diverted to  nearby airports while outbound flights were delayed for three to four hours.

Some Chinese experts claimed that the strange sight was actually debris from a US intercontinental ballistic missile.

Chinese officials later said that they knew what the object had been but were unable to make it public because there was a 'military connection.'

An official statement is expected later today.