The FDNY rescued people trapped inside after a fire broke out around 1:30 a.m. on Hoffman Street in the Belmont section.
Neighbors were horrified to learn at least two people died, with several more hospitalized with serious injuries including a 7-year-old girl.
"I just heard screaming. They were calling me, 'Carmine, Carmine,' to see if I was alright," said Carmine Auricchio, landlord. "I opened up the door. My whole upstairs was on fire."
"They were up on the roof. They had the ladders up there," said Paul Madson, a neighbor. "Everybody came down the fire escape because they said it was in the hallway, the flames."
Investigators were in and out of the five-story building all morning.
The fire started in a first floor apartment, but the FDNY says tenants who escaped failed to shut the door behind them, sending flames into the stairwell, trapping people upstairs.
"We arrived in around three minutes, so we had a very quick response, but we were met with a very heavy fire on the first floor," said Assistant Chief Roger Sakowich, FDNY.
An open door allowed fire to engulf the stairs. It was eerily similar to another deadly fire just over two months ago in the same neighborhood.
12 people died on Prospect Avenue after investigators say a little boy was left unattended playing with the stove.
"This is our people around here! It shouldn't happen. I don't understand. They know about fires. It shouldn't happen. Everybody should have an alarm in each apartment!" said Carmin Navedo, a neighbor.
Officials also say there were no smoke alarms found in the apartment where the fire started, or where the critical patients were located.
Fire Marshalls were trying to determine how the fire started, but initially said it did not appear to be suspicious.
In an emergency, firefighters stress the importance of closing doors to keep flames from spreading.
The Red Cross is assisting 20 residents, 13 adults and seven children, who were left homeless by the fire.
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