The mother and another person living in her apartment escaped the blaze, but the woman then realized her 5- and 10-year-old children were still in the building, the Times reported.
"She realized that her two children were not outside and she went inside to rescue (them) and unfortunately all three of them have perished in this fire," Hillsborough County Sheriff Chad Chronister said at a news conference.
During the news conference, Chronister said, “I don’t even know how to comment” about the mother’s attempt to save her children.
"For a mother's love to go back in, and know that my children may be inside, not knowing that they were inside -- but they may be inside -- she lost her life because of it,” Chronister said. “I mean, is there any greater actions of love than the one displayed by this mother today?”
The names of the woman and her children have not been released, pending notification of next of kin, WTSP reported.
According to WTVT, Carmella Ortiz, who identified herself as the roommate of the deceased woman, said she originally thought the fire was a false alarm. Ortiz and her daughter exited the apartment, along with the mother of the two children.
"We all kind of all three of us just look at each other like, 'What the hell is going on?' We thought it was a false alarm," Ortiz told WTVT. "She was a good mom. Like every mom, you know, you just want what's best for your kids."
"There had to have been something (in the apartment) stopping her," Ortiz told the television station.
All eight apartments were damaged by the flames, smoke and water, and at least 12 residents were displaced because of the blaze, the Times reported.