PHILADELPHIA — A large house fire in Philadelphia early Wednesday caused the death of at least 13 people, including seven children, and two others were injured, according to WPHL.

Fire officials warned the numbers could grow as firefighters inspected the rowhome, where officials said 26 people had been staying.

The blaze’s cause was not determined, but officials shaken by the death toll — apparently the highest in a single fire in the city in at least a century — vowed to get to the bottom of it.

Firefighters and police responded to the fire at the three-story rowhouse in the city’s Fairmount neighborhood around 6:40 a.m. and found flames coming from the second-floor windows, fire officials said. The house had been converted into two apartments, police said.

City and fire officials did not release the names or ages of those killed in the blaze.

“I knew some of those kids — I used to see them playing on the corner,” said Dannie McGuire, 34, fighting back tears as she and Martin Burgert, 35, stood in the doorway of a home around the corner. They had lived there for a decade, she said, “and some of those kids have lived here as long as us.”

One of the two people injured was also a child. Both were taken to local hospitals.

According to investigators, eight people were living in a first-floor unit of the duplex, and 18 were living in a unit that occupied both the second and third floors.

Philadelphia Fire Department First Deputy Commissioner Craig Murphy said the odd configuration of the house made it difficult to navigate, but crews were able to bring it under control in less than an hour.

Officials said eight people were able to evacuate the building. The four smoke alarms in the building, which was public housing, did not appear to have been working, fire officials said.

The alarms had been inspected annually, and at least two had been replaced in 2020, with batteries replaced in the others at that time, Philadelphia Housing Authority officials said.

Television news footage showed ladders propped up against the smoke-blackened front of the house, with all its windows missing. Holes remained in the roof where firefighters had broken through.

The Philadelphia Fire Department is working with the city’s fire marshall office to determine a cause.

The Associated Press contributed to this report.