New Yorkers were alarmed yesterday after a mysterious glowing object was spotted flying over the city.

Hundreds of pedestrians stared and pointed to the sky and traffic was at a standstill as the object appeared to hover high above the city skyline.

The Federal Aviation Administration and city police departments received several calls from 1.30pm local time with reports of the object initially being sighted in Manhattan's Chelsea area and later spread across the city.

Law enforcement sources said they believed the object was likely to be some sort of balloon but were unable to confirm exactly what the bright silver sphere was.

Aviation authorities said they had since reviewed radar data but could not find anything out of the ordinary.

FAA spokesman Jim Peters said: "We re-ran radar to see if there was anything there that we can't account for but there is nothing in the area."

"There was some helicopter traffic over the river at that time and we checked with LaGuardia Tower. And they said they had nothing going low at that time."

Police officials said they had not been notified of any planned weather balloon releases.

Eye-witness Daniel Calhoun, 52, said: "Common sense says it was a plane or a balloon, but this thing stopped everyone in the street for two blocks. Any New Yorker will tell you, that alone is extraordinary."