A young FDNY firefighter died Sunday after battling a raging three-alarm inferno at a Brooklyn home where seven of his colleagues were also injured, officials said.

The body of a man who lived in the house was found Sunday night in the burned-out wreckage, FDNY officials and Mayor Adams’ spokesman Fabien Levy confirmed.

Six-year veteran firefighter Timothy Klein, 31, died while trying to knock down the blaze at the home on Avenue N near E. 108th St. in Canarsie that erupted about 1:40 p.m.

Klein was cut down when the building ceiling collapsed; the critically injured firefighter was rushed to Brookdale University Hospital Medical Center in Brooklyn but could not be saved.

“The incident commander identified deteriorating conditions and ordered all members out of the building,” said acting FDNY commissioner Laura Kavanagh at a grim news conference at Brookdale.

”As they were doing so, there was a partial collapse of the ceiling. Four members were caught in that collapse. Three made it out and are stable in local hospitals at this time,” she reported.

An injured civilian was treated at the scene.

Five injured firefighters were being treated at local hospitals. Their injuries did not appear to be life-threatening Sunday evening, Mayor Adams said at the somber news conference.

There was no information on what sparked the deadly blaze.

In a heartbreaking moment of grief, about 100 FDNY members saluted as Klein’s body was transferred from the hospital to a waiting ambulance. Relatives of Klein stood by, sobbing and hugging in helpless sorrow.

“We pray for him and his family, for the city, a great loss,” Adams said. “Timothy lost his life doing the job that we ask of him every day, and his fellow colleagues.”

Firefighters were working to track down one resident of the burned-out home who was unaccounted for, Adams said.

Elaine Giddings, 73, whose daughter Elizabeth Giddings lives in the house that burned with her son Carlos Richards, 21, told The News that Richards had not been immediately found.

“My daughter’s house burned down,” Giddings said. “I don’t know where she is. Her son, I don’t know what happened, they can’t find her son. All of her children went out looking for him in the street.”

Giddings was not immediately available to comment on the FDNY discovering a body Sunday night.

Kavanagh said Klein — assigned to Ladder 170 in Canarsie — was the 1,157th member of the department to die in the line of duty.

“Firefighter Klein is a hero to this city, this country, and his fellow firefighters, and will be eternally remembered for making the ultimate sacrifice so that others may live,” Andrew Ansbro, president of the FDNY-Firefighters Association, said in a statement.

The inferno escalated quickly, going to a third alarm when the flames engulfed the house, the FDNY said.

Firefighters found “a very heavy fire condition on two floors of the building,” Acting Chief of Department John Hodgens said.

Klein was on a “nozzle team,” making him one of the first firefighters to step into the burning building.

“Talking to members at the scene, they were extinguishing fire and everything seemed to be going routine, when suddenly the entire second floor became engulfed in flames,” Hodgens said.

Three members of the team were able to flee the flames by jumping out windows and climbing down ladders to other areas of the house.

“Our members worked feverishly and very hard under very difficult conditions to try to reach him,” Hodgens said. “Unfortunately, they were not able to get to him in time, and he succumbed to his injuries.”

A helicopter hovered over the scene, while hundreds of neighbors crowded around the emergency tape blocking off the street.

Paul Jackson, who lives behind the badly burned home, watched as flames quickly tore through the house.

“I see the fire coming out, at first it was on one side of the house, and it came to the other side of the house,” said Jackson, 28. “By the time I saw it, it was already too late, like half of the house was burning down.”

Neighbors watched as firefighters were pulled out of the home on stretchers.

“One was unconscious, one had a lot of black stuff on his face,” said a neighbor, who did not give his name. “It looked very terrible.”

First responders were performing CPR on the firefighter, he said.

Jackson saw the critically injured firefighter geared up and ready to run into the flames. Shortly after, he was also carried out of the house on a stretcher, blue-faced and “lifeless.”

“They pumped,” said Jackson, 28. “His stomach went up, it was basically like they were trying to save him.”

Euline Robin, 74, another longtime neighborhood resident, described a chaotic scene.

“By the time we came, the firemen were running back and forth, trying to hook up to get water, that’s what I saw.” she said. “I saw them doing CPR on somebody, but I don’t know who it was. They were pumping his chest.”

Klein, whose father was a member of the department and whose family has a “rich history of service with the FDNY,” eulogized probational firefighter Steven Pollard, 30, who died in January 2019 after he fell to his death from a Belt Parkway bridge in Brooklyn while responding to a car crash, Mayor Adams said.

As of Sunday afternoon, 33 FDNY units and 106 firefighters had responded to the blaze. Firefighters were still working at the scene Sunday evening, the FDNY said.

Klein is the latest of New York’s Bravest to die in the line of duty while heroically serving the city.

Firefighter Jesse Gerhard, 33, collapsed inside his Queens firehouse Feb. 16 a day after responding to a fire inside a three-story home on Beach Channel Drive near Beach 25th St in Far Rockaway.

Gerhard had a medical episode while he was on duty at his firehouse, Ladder Co. 134 in the same neighborhood.

His colleagues at the firehouse performed CPR and rushed him to St. John’s Episcopal Hospital, where he later died.