Police received calls around 8:49 a.m. reporting that manhole covers had been blown off at the an intersection in the heart of the downtown district, said department spokesman Gene Harley. About an hour later, firefighters had put out three separate fires where the covers blew off.

Georgia Power spokesman Jeff Wilson said what caused the explosion in the utility's cable network was not immediately clear. It could take several hours for crews to get underground to begin investigating what happened, he said.

Police evacuated shoppers and pedestrians after the explosion but allowed business owners and employees to stay behind to secure their shops. Harley said employees at City Hall, right in the center of the affected area, were sent home for the day and authorities were encouraging businesses to do the same.

Power was out in a large section of downtown, Harley said, and extra city police officers and Chatham County sheriff's deputies were brought in to help direct traffic away from the area.