At least 19 people have died, including 9 children, when a fire broke out at Twin Parks Apartments in Bronx, New York.

According to New York Fire Department, the tragedy begin around 11 a.m. Sunday in a duplex apartment on the 2nd and 3rd floor. It rapidly spread to other units in the high-rise building. It’s unclear what started the fire but FDNY doesn’t believe it’s suspicious. However, he does think the fire escalated because the door from the apartment was left open.

FDNY Commissioner Daniel Nigro said the blaze sent 32 people to the hospital with life-threatening injuries. A total of 63 were injured.

“There were certainly people trapped in their apartments all through this building,” Nigro said, calling the smoke conditions “unprecedented.”

Victims were found in stairways of every floor of the building, many in cardiac arrest. The majority of the injuries were from smoke inhalation. The victims were sent to at least 5 area hospitals.

The names and ages of the victims have not been disclosed yet.

“This is going to be one of the worst fires we have witnessed here in modern times in the City of New York,” Mayor Eric Adams said at a press conference.

Video footage shows two teens, an 18-year old girl, and 13-year old boy, escaping the fire by climbing out of a window and down the pole.

Sources close to ABC News say that a space heater is being investigated.

The fire has been put out and help is on the way. The American Red Cross is there to immediately assist residents with food and shelter.

New York Gov. Kathy Hochul tweeted that she was “horrified” by the fire Sunday.

“My heart is with the loved ones of all those we’ve tragically lost, all of those impacted and with our heroic  @FDNY firefighters,” Hochul wrote. “The entire State of New York stands with New York City.“