At least four smoke detectors in the Philadelphia row house that caught fire Wednesday morning did not work properly during the blaze, a city fire official confirmed Wednesday.
The fire,"one of the deadliest residential fires in the city's recent history," writes The New York Times, began around 6:40 a.m. and killed at least 13 people, including seven children.
"There were four smoke detectors in that building, and none of them operated," said Philadelphia Deputy Fire Commissioner Craig Murphy during a news conference, per CNN.
The official also said there were 26 people in the building at the time of the fire, including eight on the first floor. "That is a tremendous amount of people to be living in a duplex," he added, describing the blaze as "one of the worst fires" he's ever seen.
"This is without a doubt one of the most tragic days in our city's history, the loss of so many people in such a tragic way," said Philadelphia Mayor Jim Kenney. "Losing so many kids is just devastating."
The building in question was run by the federally funded Philadelphia Housing Authority and not the city, the Times writes. The fire's cause reportedly remains under investigation.