Blue light in sky mystifies New Yorkers

An explosion at a power station in New York has turned the sky an eerie blue, with thousands of people mystified until an explanation was offered.

The blue light over New York City. Source: AAP

A transformer explosion at an electric power substation in the New York City borough of Queens has lit up the night sky with a bright blue light, mystifying some residents, but officials said no one was injured in the incident.

"The light you have seen throughout the city appears to have been from a transformer explosion at a [power company] Con Edison facility in Queens," the New York Police Department said in an advisory on to residents on Twitter.

"The fire is under control, will update as more info becomes available," it said.

Many social media users posted videos and photos of the night sky over New York City illuminated by a bright light.

The New York City sky lit up on Thursday. Source: AAP

"Why is the sky lit up bright blue in Queens New York City right now? Is it fireworks?" Louis Santoro, a New York City resident, wrote on Twitter.

New York City Mayor Bill de Blasio said on Twitter that no one was injured and that Con Edison was evaluating the extent of power outages in the area.

Con Edison said on Twitter an electrical fire at a substation in the Astoria section of Queens caused a transmission dip in the area.

The cause of the incident was being investigated, it said.