PHOENIX -- One person is dead after an early morning apartment fire that also displaced six families.

Neighbors reported hearing explosions

It happened shortly after 2 a.m. Thursday at Fifth Avenue and Osborn Road in central Phoenix.

Neighbors reportedly tried to help the elderly man, but they could not get through the flames to him.

One neighbor said an explosion knocked him back into a wall.

The fire started on the ground floor and quickly worked its way up.

Crews were able to douse the flames, but not before the 65-year-old man perished.

Firefighters have not determined the cause of the fire, but they do believe it started in the man's apartment. He reportedly was a smoker and also used oxygen.

Six families will have to find other places to stay until they're allowed back into their apartments. The Red Cross is stepping in to help those people.