The National Weather Service said there is no evidence of any naturally occurring phenomenon to explain bright lights in the eastern sky that prompted hundreds of calls to the service and emergency officials.
Callers from Maryland, Virginia and North Carolina described brilliant, streaking lights followed by an explosion-like sound around 9:45 p.m. Sunday.
A spokesman for the weather service's Wakefield office said the lights are "nothing meteorological that we can see."
Callers reported seeing "great balls of fire" lighting up the sky in shades of yellow, white orange and blue. Some described the explosion as sounding like thunder.
The weather service said no damage was reported.