Fire tore through a row house early Monday, killing two young children and two adults in the city's third fatal blaze in a week.
The blaze broke out at the two-story home in west Philadelphia shortly before 4:45 a.m., Executive Chief Richard Davison said. A 23-year-old woman was pronounced dead at the scene, and a 2-year-old boy, a 4-year-old boy and a 68-year-old man were pronounced dead at a hospital.
The fire marshal's office was investigating, and there was no immediate word on the cause of the blaze, which was declared under control in less than 45 minutes, Davison said. Firefighters did not find any smoke detectors.
The identities and relationships of the victims were not released.
The American Red Cross of Southeastern Pennsylvania was planning to assist one man who was not at home at the time, spokesman Dave Schrader said. The organization was also helping neighbors to clean their homes.
The fire deaths marked the sixth in two days in the city, after a 4-year-old girl and her 79-year-old great-grandmother were killed in a house fire in north Philadelphia on Sunday morning.
Lt. Robert Neary, 60, and firefighter Daniel Sweeney, 25, were killed a week ago in a building collapse at a furniture store near a warehouse that was on fire. No cause has been determined in that fire.
The city has had 14 fire fatalities so far this year, two fewer than the 16 at the same point last year, Davison said.