Nine children among 19 dead in Bronx blaze

A faulty heater sparked a fire that filled a Bronx apartment building with thick smoke, killing 19 people including nine children in New York's deadliest fire in three decades.

Fire commissioner Daniel Nigro said the fire "started in a malfunctioning electric space heater" in an apartment unit spanning the second and third floors of the 19-storey building.

The door of the apartment was left open, allowing smoke to quickly spread throughout the building, Nigro said.

Some residents, trapped in their apartments, broke windows for air and stuffed wet towels under their doors. One man rescued by firefighters said he'd become numb to fire alarms because of frequent false alarms.

Some residents "could not escape because of the volume of smoke," Nigro said.

Firefighters "found victims on every floor and were taking them out in cardiac and respiratory arrest," he said.

Thirteen people remained hospitalised in critical condition.

Most of the victims had severe smoke inhalation, Nigro said.

About 200 firefighters responded to the fire on Sunday.

News photographers captured images of firefighters entering the upper floors of the burning building on a ladder, multiple limp children being given oxygen after they were carried out and evacuees with faces covered in soot.

Building resident Luis Rosa said he was awakened by a fire alarm, but dismissed it at first, thinking it was one of the building's periodic false alarms.

But when a notification popped up on his phone, he and his mother began to worry. By then, smoke began wafting into his 13th-floor apartment and he heard sirens in the distance.

He opened the front door, but the smoke was too thick for an escape, he said.

"Once I opened the door, I couldn't even see that far down the hallway," Rosa told The Associated Press.

"So I said, OK, we can't run down the stairs because if we run down the stairs, we're going to end up suffocating.

"All we could do was wait."

The 120-unit building in the Twin Parks North West complex was built in 1973 as part of a project to build modern, affordable housing in the Bronx.

The death toll is the city's highest since a 1990 blaze at the Happy Land social club where 87 people were killed when a man set fire to the building after arguing with his former girlfriend and being thrown out of the Bronx club.

Sunday's fire happened just days after 12 people, including eight children, were killed in a house fire in Philadelphia.