NEW YORK — The deadliest residential fire to hit New York City in at least a quarter century swept through a Bronx apartment building Thursday on one of the coldest nights so far this winter, killing 12 people and leaving four more fighting for their lives, city officials said.

The dead included a child around a year old, New York City Mayor Bill de Blasio said during a briefing outside the building.

"We may lose others as well," he added.

Fire Commissioner Daniel Nigro called the fire, "historic in its magnitude," because of the number of lives lost. Excluding the Sept 11 attacks, it was the worst fire in the city since 87 people were killed at a social club fire in the Bronx in 1990.

"Our hearts go out to every person who lost a loved one here and everyone who is fighting for their lives," Nigro said.

The blaze broke out on the first floor of a five-story building just before 7 pm and quickly ripped through the roughly century-old structure, which stands in a row of similar apartment buildings a block from the grounds of the Bronx Zoo.

The cause remained under investigation.

About 170 firefighters worked in bone-chilling cold, just 15 degrees, to rescue people from the building. Water sprayed from hoses froze on the street.

Thierno Diallo, 59, a security guard originally from Conakry, Guinea, who lives in a ground floor apartment said he was home asleep when he heard banging on the door. It took him a moment to realize what was happening.

"Only when I heard people screaming, 'There's a fire in the building!'" he said. "I heard somebody, 'Oh! Fire! Fire! Fire!'"He ran out in his bathrobe, jacket and sandals.

Kenneth Kodua, 37, said he left his apartment to get food, leaving his roommate behind, and came back to find people fleeing in a panic.

Hours later, he was still trying to find out whether his roommate escaped.

"I tried calling her. I tried calling. No answer," he said, still clutching his bag of uneaten food. His phone was dead.