New York, Dec 28 (IANS): A transformer explosion at a power plant in Queens temporarily lit up the New York skyline in bright blue and caused a frenzy in the city, with many on the social media fearing an alien invasion.

The New York City Police Department (NYPD) wrote on Twitter that the blue light came from a transformer explosion at a Con Ed facility on Thursday night and added that the fire from the explosion was under control.

The explosion lit up the sky in shades of blue visible as far as Manhattan and New Jersey. The tremors shook buildings and rattled windows, sending people running into the streets.

The explosion was determined to be a non-suspicious equipment malfunction, the NYPD tweeted, adding that there were "no injuries, no fire, no evidence of extraterrestrial activity".

Residents reported temporary power outages.

LaGuardia Airport in Queens initially grounded all flights following the explosion. No flights took off between 9.22 and 10.23 p.m. ET, according to flight tracking data company FlightAware.

All terminals were impacted by the loss of commercial power, causing the Federal Aviation Administration to issue a temporary ground stop. The airport later resumed normal operations.

Twitter users, unsure of what had caused the light, shared photos and videos of New York City's sky. Many on the social media feared it as an alien invasion.

"We thought it was a UFO," said Yiota Androtsakis, a longtime Astoria resident.

An NYPD official said the bright lights and loud bangs caused a surge of 911 calls, with residents reporting explosions and one person calling in a plane crash.