'Arson' kills five at migrants' home

The early morning blaze at the Brooklyn building is being investigated as a possible case of arson because it started behind the door of the first-floor entrance to the building, New York City Fire Commissioner Salvatore Cassano said.

"That's not where a fire would normally start," Mr Cassano said after surveying the devastation of the fire, which trapped residents and caused the interior walls to collapse.

"That's why this is a fire that we are saying is very likely to be incendiary."

Four people in the building were injured, including an infant and a child who were tossed out the window by a woman frantically trying to save them.

The infant was in critical condition with a fractured skull after bystanders below failed to catch him, officials and witnesses said. The other child landed on an awning.

At least one adult was taken to hospital, and 13 firefighters were injured, none of them seriously.

The fire started at about 2.30am local time and flames quickly engulfed the three-story building on a busy commercial strip, consuming a ground-floor Japanese restaurant and two apartments on the upper floors.