House fire which killed 12 caused by child setting Christmas tree alight

A fire that killed a dozen people, including nine children, was started when a Christmas tree was set ablaze with a lighter by a five-year-old, top fire officials have said.

Preliminary findings of an investigation said the fire in Philadelphia, in the US, was “99 to 100%” started when the Christmas tree was set on fire.

Philadelphia Fire Commissioner Adam Thiel said that the child believed to have started the fire, who is one of only two survivors, was the only person on the first floor of the building when the blaze began.

Previous reports said it was suspected the fire had been started this way , but the theory has now been confirmed.

At a news conference Thiel said: “We believe with certainty, so 99 to 100% confidence, that the first item ignited in this blaze was a Christmas tree on the second floor.”

Relatives and family members watch as emergency services work at the scene of the deadly blaze (AFP via Getty Images)

He added: “We are left with the words of that five-year-old child, that traumatised five-year-old child, to help us understand how the lighter and the tree came together with tragic consequences."

The commissioner said that despite finding seven smoke alarms in the building, only one of them sounded during the fire.

Four were found in drawers, one on the floor with its battery out, and another, still attached to the ceiling, with its battery also removed.

Windows are pictured from the scene of the fatal fire in the Fairmount neighborhood, Philadelphia (Getty Images)

The only alarm that did sound was in the basement.

The fire department classified the fire as "incendiary," saying it believed "there was some type of human intervention to bring the ignition source to the first item ignited".

The fire broke out around 6:30 a.m. (1130 GMT) on the second floor of a three-story row house in the city's Fairmont neighborhood.

Philadelphia's deputy fire commissioner said: "I've been around for 35 years now and this is probably one of the worst fires I've ever been to." (Sky News)

The building is owned by the federally funded Philadelphia Housing Authority, the fourth-largest housing authority in the United States.

The tragedy - along with a fire in New York City on Sunday that claimed the lives of 17 people, including eight children - has stirred questions on safety standards in low-income city housing in the United States.

Philadelphia fire officials said the building was overcrowded, with about two dozen people inside a structure meant to accommodate two families.

Residents hug in the streets where one of the deadliest blazes in recent memory took a dozen lives (AFP via Getty Images)