Firefighters were called to a house converted into two apartments in the Fairmont neighbourhood at 6.40am local time on Wednesday.

Eight people managed to escape and a child and an adult were taken to hospital. The fire was brought under control after less than an hour.

There were four smoke detectors in the house - owned by the city's public housing authority - but they didn't activate, officials said.

TV pictures showed ladders up against the smoke-blackened front of the three-storey house and holes in the roof where firefighters had broken through.

"I knew some of those kids - I used to see them playing on the corner," said local resident Dannie McGuire, 34, who added that the children had lived there for a decade.

"Losing so many kids is just devastating. Keep these babies in your prayers," said Philadelphia mayor Jim Kenney.

Philadelphia Deputy Fire Commissioner Craig Murphy added: "I've been around for 35 years now and this is probably one of the worst fires I've ever been to."