A major fire in the New York borough of the Bronx on Sunday has left at least 19 people dead, including nine children, with 63 people injured.

The five-alarm fire started before 11 a.m. in a duplex apartment located on the second and the third floor in the Tremont neighborhood.

Around 200 New York fire department members were present to put out the fire of the 19-story high-rise building at 333 East 181st Street.

​​Victims were reportedly found in the stairwells on every floor, with many suffering from cardiac arrest. Meanwhile, a majority of the injuries sustained were from smoke inhalation.

During a press conference on Sunday, FDNY Commissioner Daniel Nigro said firefighters had found the apartment door to the duplex open, which caused the smoke to spread quickly and accelerated the fire.

“That is unprecedented in our city. We expect there to be numerous fatalities,” Nigro said.

The commissioner compared the blaze to the 1990 Happy Land social club fire, which killed 87 after a man set the building on fire following an argument with his ex-girlfriend and was removed from the venue.

Of the 63 injured, 32 people suffered life-threatening injuries, 22 people had non-life-threatening injuries, and nine people were in serious condition. The 32 injured were rushed to five different hospitals in the Bronx.

Cristal Diaz, 27, a resident of the building, revealed she was in her living room when she began to smell the smoke.

“We started putting water on towels and the bottom of the door. Everything was crazy,” Diaz told local media. “We didn’t know what to do. We looked out the windows and saw all the dead bodies they were taking with the blankets.”

While officials don’t believe the fire is suspicious, an investigation is underway to determine the cause of the blaze.

This is a representational image. AFP / Ed JONES