Two or three explosions in the basement of an office building rocked central Philadelphia on today, leading to evacuations but no injuries, police said.
Workers for the PECO utility who were working in a building in central Philadelphia reported the underground explosions, said Lisa Rotolo, a spokeswoman for the Philadelphia police.
Ms Rotolo said some parts of the surrounding area had been sealed off by police. She would not comment on media reports that the explosion was caused by an electrical fault. The cause was not immediately known.
Fox television news reported an apparent utility malfunction caused the explosion. CNN quoted the FBI as saying there was no apparent link to an extremist attack.
