AUSTIN (KXAN) — Residents of 12 units in an east Austin apartment complex were displaced after an overnight fire late Wednesday.

It happened at the Mueller Flats Apartments on Clayton Lane, near the intersection of I-35 and Hwy 290.

The Austin Fire Department responded to the fire around 10:30 p.m. Wednesday and found flames that were 10-15 feet above the roof line.

The fire started on the third floor balcony because of improperly discarded smoking materials, according to AFD. The fire spread to the attic and second floor, AFD said.

Firefighters had to rescue residents who were trapped on the third floor. AFD said no one was hurt in the fire.

There are 24 apartment units in one building; six of the units in the building had heavy fire damage and six had fire control damage. Occupants of the 12 affected units were displaced, according to AFD.