A young boy died and four of his family members were critically hurt after a lithium-ion battery fire broke out in their Bronx apartment early Wednesday, the FDNY and neighbors said.

Firefighters responded to a blaze on the 11th floor of a building at NYCHA’s Patterson Houses, on Morris Avenue in Mott Haven, just before 1 a.m., authorities said.

Five people, including three children and two adults, were rescued from the apartment. A boy — who neighbors said was as young as 9 years old — was taken to NYC Health + Hospitals/Jacobi, where he was pronounced dead.

Neighbors said his brother was also taken there in critical condition.

The third sibling, a 15-year-old boy, was taken to NYC Health + Hospitals/Lincoln, while two adults — a 37-year-old man and a 33-year-old woman — were taken to NYC Health + Hospitals/Harlem. All are considered to be in critical condition.

Firefighters were able to get the fire under control in less than an hour. FDNY officials determined a lithium-ion battery from an e-bike caused the deadly blaze.

Neighbors said the e-bike was stored near the stove in the apartment, which is right near the front door, trapping the family inside behind the flames.

In a statement, state Assembly Member Amanda Septimo said: “My heart goes out to this family as they face an unimaginable loss. No family should have to endure such a tragedy, and I am hoping for the full recovery of those injured.”

“I ask that you join me in keeping this family and our entire Patterson Houses community in your hearts during this incredibly difficult time,” Septimo added.

The FDNY commissioner and Mayor Zohran Mamdani are expected to hold a press conference about the fire around 11 a.m.