JACKSONVILLE, Fla. -- One of two people pulled from a burning travel trailer before dawn Tuesday has died and the second is hospitalized with serious injuries.

The fire started about 3 a.m. Tuesday in a travel camper in the Royal Court mobile home park in the 5500 block of Timuquana Road.

"Flames shooting in the air, about 20 to 30 feet up," said witness Wanda Powell. "They got it out pretty quickly."

Two unconscious adults were found on the floor out of the RV -- a woman who died at the scene and a man who was rushed to a hospital and reported to be in critical condition, according to Jacksonville Fire-Rescue spokesman Tom Francis.

A man who said he got out of the burning trailer told arriving firefighters that three people were left inside.

"The potential third victim within the camper, a female, was not found in the camper, nor was she found in the immediate vicinity in the compound itself," Francis said.

Police have not released the names of the victims, but officers remained on the scene at noon and the investigation continues.

Firefighters had not yet determined a cause of the fire. The state fire marshal is also investigating.