Firefighters battled a relentless early-morning apartment fire on the city’s near north side.

(IFD photo)

Firefighters battled a relentless early-morning apartment fire Thursday on the city’s near north side.

About 4:15 a.m., Indianapolis Fire Department crews were dispatched to the 300 block of East 31st Street on reports of a structure fire.

When they arrived, they found heavy smoke and fire shooting through the roof of the building.

Detectives said one person lives in one of the units, but the resident was not at home at the time of the fire.

Crews battled the blaze for nearly an hour before gaining control of the flames.

Officials said there were no working smoke detectors inside the building, and the cause of the fire remained under investigation.

No injuries were reported.