The blaze broke out at 470 Martin Luther King Drive — a two-story attached home — around 11:30 p.m., city and county officials said.
The child on the first floor apparently attempted to save the infant sleeping upstairs, Wallace-Scalcione said.
Arriving firefighters found both the baby and girl at the scene. The girl was pronounced dead and the baby was taken to a local hospital, where he was pronounced dead, Hudson County Prosecutor Esther Suarez said.
The childrens' mom and a 6-year-old boy able to evacuate before firefighters arrived.
The origin and cause of the fire were under investigation. The cause and manner of death is pending with the Regional Medical Examiner.
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