UPDATE: A fire that raced through a row of two-story homes in southwest Philadelphia early Saturday, killing three 4-year-olds and a baby and engulfing at least 10 houses, may have started in a couch on a porch, officials said.

The blaze began shortly before 3 a.m. and was brought under control in about an hour, fire officials said. At least eight row homes were completely gutted, leaving behind only charred frames. The cause of the fire remains under investigation.

A fire department dispatcher identified the victims as 4-year-old twin girls, a 4-year-old boy and a month-old boy. The relationship between the twins and the two boys was unclear. Four other people were injured.

PHILADELPHIA (AP) — A fast-moving fire raced through a row of two-story homes in southwest Philadelphia early Saturday, killing four children, engulfing at least 10 houses and displacing more than 40 residents, officials said.

Rowhouse Inferno Kills Four Children, Destroys Nearly a Dozen Homes

A woman cries as she walks past Philadelphia firefighters working on burned row homes on Saturday, July 5, 2014, in Philadelphia. A fast-moving fire in southwest Philadelphia early Saturday left four children dead and burned through a number of adjoining homes. (AP Photo/Michael Perez)

The blaze began shortly before 3 a.m. and was brought under control in about an hour, fire officials said. At least eight row homes were completely gutted, leaving behind only charred frames, and four others were injured, authorities said.

Jeff Boone told The Philadelphia Inquirer that he saw a couch on fire on the porch of a house about five doors down from his residence and heard children screaming.

The flames spread across porches so fast, he said, that “it looked like someone had a flamethrower and just shot it all across.”

He called 911 and bolted out of his house to try to save his neighbors, the 27-year-old Boone said.

“I was running, screaming, telling everybody, ‘Get up! Yo, get yo! Go!’” he said.

Rowhouse Inferno Kills Four Children, Destroys Nearly a Dozen Homes

Philadelphia firefighters watch as a front wall collapses from a burned row home on Saturday, July 5, 2014, in Philadelphia. Authorities say the fast-moving fire early Saturday has killed four children. Fire department officials say there is no immediate word on how many others were injured in the blaze that destroyed eight homes in the row and engulfed a total of 10 houses. (AP Photo/Michael Perez)

Milton Musa told the newspaper his roommate woke him up and said their home was on fire. Once outside, Musa said, he saw two children hanging from a neighbor’s window.

“I could see they weren’t strong, and I was afraid they’d fall to the cement,” Musa said. “So I went underneath them, let them fall on my back and carried them away.”

He wiped away tears as he recalled the intense moments as the blaze swept through the neighborhood.

“Everyone was running for their lives,” he said. “I’ve lost everything. My paperwork, my documents, my house. Everything.”

There was no immediate word on what may have caused the fire.

Rowhouse Inferno Kills Four Children, Destroys Nearly a Dozen Homes

Philadelphia firefighters work on burned row homes on Saturday, July 5, 2014, in Philadelphia. A fast-moving fire in southwest Philadelphia early Saturday left four children dead and burned through a number of adjoining homes. (AP Photo/Michael Perez)

“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 said 42 people were displaced by the fire.

This story has been updated.