The victims were trapped in the home, at the intersection of Trenton and Maryland avenues, just after 6:30 a.m.
Police say an elderly woman died in the blaze.
Her husband remains at St. Joseph's Regional Medical Center with burns to the back of his neck.
Their grandchildren were taken to Jacobi Medical Center in the Bronx in critical condition, suffering from smoke inhalation.
The residents were pulled from the burning building by responding firefighters.
Authorities say 9 people lived in the house. The fire started in the rear of the first floor.
One person suffered broken bones when jumping from the burning building.
Three firefighters were hurt while pulling the victims from the flames.
The fire burned so hot that it tore through their protective gear.
The cause of the fire is under investigation.
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