Fire swept through a multi-unit building in the city’s Mansion neighborhood Monday night killing one person and forcing at least two people to jump to safety from an upper floor.

Fire Chief Robert Forezzi said a body was found in a basement apartment shortly after firefighters entered the structure at 69 Grand St. Authorities did not know the victim’s name or gender.

Albany police spokesman Detective James Miller said in a statement to reporters that there was one female resident who could not be accounted for.

The fire, which began shortly before 8 p.m., also forced at least two people to jump from the upper porch in the back of the burning structure before crews arrived shortly after the 7:51 p.m. call. Others also had to be rescued, Miller said.

Authorities also did not know the identities and conditions of those who jumped, but a city police officer on the scene said the two appeared to be OK. Miller said the injured were taken to Albany Medical Center Hospital for treatment.

“”I have never seen a fire like that before,”” said Dennis Poormano, who watched the fire from across the street at his home on 72 Grand St. ””Huge flames were pouring out of the windows. It was like something out of a movie. It was explosive, and there was smoke everywhere. I could barely see.””

Forezzi said one firefighter had to be taken to a hospital after slipping and falling on the ice, but his injures were not serious.

The cause of the fire and how many people or apartments are in the building was not known.

Forezzi said the inferno appears to have started on the first floor or in the basement. Two alarms were sounded, he said.

At least six pieces of heavy fire equipment were called to the scene, and more than a dozen firefighters were scrambling to contain the blaze.

Several nearby streets are closed to traffic due to the blaze. They include parts of Philip to South Pearl streets off Madison Avenue, and Van Zandt Street and Ash Grove Place off Grand.