A Fountain Valley woman died and about six families were displaced during an apartment complex fire Thursday.

The Fountain Valley Fire Department responded to a fire at a 16-unit apartment complex around 5:10 a.m. in the 10400 block of Slater Avenue.

Firefighters found a 45-year-old woman alone inside one of the units as they were extinguishing the building, Capt. Nick Fasullo said.

The victim, whose name officials are not releasing, was transported to Fountain Valley Regional Hospital where she was pronounced dead.

No other injuries were reported; however, extensive damage was done to several of the units, which were red tagged, Fasullo said.

The families that were displaced are receiving assistance from the American Red Cross.

Authorities are investigating the cause of the fire.

—Anthony Clark Carpio

Twitter: @acocarpio