An unidentified flying object (UFO) disrupted air traffic over Zhejiang's provincial capital Hangzhou late on Wednesday, the municipal government said on Thursday.

Xiaoshan Airport was closed after the UFO was detected at around 9 pm, and some flights were rerouted to airports in the cities of Ningbo and Wuxi , said an airport spokesman, who declined to be named.

The airport had resumed operations, and more details will be released after an investigation, he said.

A source with knowledge of the matter, however, told China Daily on Thursday that authorities had learned what the UFO was after an investigation.

But it was not the proper time to publicly disclose the information because there was a military connection, he said, adding that an official explanation is expected to be given on Friday.

Inbound flights were diverted to the nearby airports in Zhejiang province's Ningbo and Jiangsu province's Wuxi. Outbound flights were delayed for three to four hours.

A staff member at the airport's information desk said the airport had "no idea" how many flights were affected by the closure.

At around 11 pm on Wednesday, a netizen wrote three entries announcing the airport's closure in

his microblog at Sina.com, but they were all soon deleted.

He posted an apology at midnight, saying the news had not been confirmed and asking those who had republished his earlier entries to delete them.

Source: China Daily(By Yang Yijun)