An occupant of a Jackson Heights apartment building was killed in a fire Saturday, the FDNY said.

The blaze at 37-60 88th St. was reported at 4:25 p.m. and was under control by 4:50 p.m., according to the FDNY.

It broke out on the fourth floor of the six-story brick building.

Residents said they fled when they heard fire alarms going off. They were allowed back in by early evening.

It was not clear what caused the fire, but the FDNY said fire marshalls would investigate the chain of events that started the deadly apartment building blaze.