Two firefighters were injured and a resident suffered smoke inhalation in an apartment fire Sunday morning in west suburban Aurora.

Crews were called shortly after 6:30 a.m. for reports of the fire at an apartment building in the 400 block of Flagg Street, according to a statement from the Aurora Fire Department. A resident in an upper apartment had called 911 after smoke from another unit entered his apartment and set off his smoke detector.

Firefighters arrived to find smoke showing from a lower-level apartment in the two-story building, the fire department said. The blaze was extinguished within 20 minutes.

One firefighter suffered a laceration to his finger and was treated at the scene, authorities said. A second firefighter was treated at a hospital for a minor injury and released.

The resident who reported the fire was treated at the scene for minor smoke inhalation but was not taken to a hospital, fire officials said. The residents of the unit where the fire started were not home at the time, and everyone in the building made it out safely.

The fire caused an estimated $40,000 in damage to the apartment where it started and rendered the unit uninhabitable, authorities said. The two other units sustained smoke damage but remained habitable.

The cause of the fire was under investigation.