A 3-year-old girl and the hero teen who ran back into a burning Bronx apartment building to save the child earlier this week have both died, a family member and officials said Wednesday.

The fire broke out in the 16-story building at 725 Garden St. just before 2 a.m. on Sunday, the FDNY said.

Lucas Silverio, 19, ran up to the smoke-filled 14th floor to try and find 3-year-old Yasleen McDonald who was separated from her mom in the chaos, one of the boy’s family members said Wednesday.

“Of course he tried his best. I applaud him. He died bravely,” Yasleen’s uncle, 22-year-old Luis Moreno, said Wednesday.

“He was in his apartment and he heard her crying. I wish it could have turned out different,” Moreno added.

Silverio and Yasleen were overcome by smoke in the hallway as they tried to escape and collapsed, authorities said. Both were rushed to nearby hospitals in critical condition for smoke inhalation with burns over 80% of their bodies.

The teen died in the hospital Wednesday and the child died Monday, according to family members and officials.

The blaze started in a trash compactor on the 14th floor, according to fire officials, but it was still not known Wednesday what sparked the fatal fire, which took more than an hour to get under control.

Marshalls with the FDNY were investigating.

Ten others in the building were also hospitalized in the blaze.