PHILADELPHIA — A fast-moving row house fire in southwest Philadelphia early today left four children dead, burned through a number of homes and displaced more than 40 people, officials said.

Fire department officials said the blaze destroyed eight row homes and engulfed at least 10 houses. There was no immediate word on other injuries or the cause of the fire.

The fire started shortly before 3 a.m. today and was brought under control by about 4 a.m., officials said.

“This is a tragic, tragic day for the city of Philadelphia. Tragic,” Fire Commissioner Derrick Sawyer said. “We lost four children today.”

The Red Cross says 42 people have been displaced by the fire.