200 firefighters responded to the fire that started around 5:30 a.m. on the first floor of 1547 Commonwealth Ave. on the corner of Commonwealth Avenue and East Tremont Avenue.
The Fire quickly spread through the four-story building in the Bronx Tuesday morning.
At least 16 people were injured after a major fire broke at an apartment building in New York's Bronx area today.
The New York Fire Department said the condition of the injured was non-life threatening.
WNBC-TV reports at least 150 firefighters are battling the fire.
There are twelve apartments in the building. That inferno killed 12 people, four of them children.
One resident told NBC news he fled the building, barefoot and barechested, with his three children into freezing temperatures that dipped as low as minus 10 degrees Celsius. "By the time we opened the door in the hallway, there was black smoke".
Over 20 fire extinguishing vehicles and more than 100 firefighters are trying to extinguish the blaze. Nigro said authorities would enter the building to determine the cause of the fire once it's deemed safe.