JACKSONVILLE, Fla. -- Two children died early Monday in a small fire in a mobile home at the Magnolia Circle Mobile Home Park off 103rd Street, according to Jacksonville Fire-Rescue personnel.

About 6 a.m., a mother found that a small fire in the bedroom where her 5-year-old daughter and 7-year-old son sleep had apparently burned itself out. She carried the children outside, but they could not be revived.

The 36-year-old mother, Amy Bullock, was taken to Baptist Medical Center for treatment of smoke inhalation. She was reported to be on a ventilator, but expected to recover.

The father, works overnight, came home to learn his two children -- Ashley and Robert "Buddy" Bullock Jr. -- had died.

"They were sweet, lovable kids," said a neighbor whose children played with Ashley and Buddy. "My heart goes out to her and her family."

Fire department spokesman Tom Francis said he'd never seen fire that required such a small firefighter response had such "an incredibly tragic outcome."

Francis said the investigation into the cause was continuing, the suspect some type of electrical malfunction. He said firefighters found some type of electrical device melted beyond recognition in the children's room.

Investigators said the home had three smoke detectors, but none of them had batteries or were wired into the home's wiring.

"It was shocking to hear that we lost two kids in our neighborhood," neighbor Roxanne Bivens said. "We love our kids here."

A man who told Channel 4's Emily Pantelides that he had a 13-year-daughter with Bullock, is thankful the older girl didn't follow through on plans to spend the night in the trailer.