A massive warehouse fire early Monday spread to a three-story building behind the structure, and a large section of one of the buildings collapsed.
The cause of the fire was unknown, and fire marshals were unable to get inside, Philadelphia Fire Department supervisor Ray Pascucci said. No one was in the buildings, he said.
He did not know what the warehouse or the other building were used for.
The fire, in the Frankford area of northeast Philadelphia, was called in about 2:48 a.m.