The source of what appeared to be "loud booms or explosions" heard Thursday night in various parts of the city remains unknown, the assistant police chief said.

Dispatchers at the Philadelphia Police Department answered five calls between 9:50 p.m. and 11:17 p.m. from residents reporting hearing "loud booming sounds," Assistant Police Chief Julian Greer said.

"Officers were dispatched to several areas trying to locate it, but they never could," he said.

Residents along the areas of Robin Hood Circle, Woodbriar Lane, Hospital Road, Pleasant Valley, Byrd Avenue and Rea Street reported hearing the "booming sound" to police.

Residents in other areas of the city reported hearing the "booms" as well.

Anyone with any information was asked to call the police department at 601-656-2131.