AUSTIN — AUSTIN -- One cigarette is to blame for a large fire that destroyed 24 apartments and displaced dozens in South Austin Tuesday, Austin Fire said.

Twenty-four units and the leasing office at Mission James Place located at 4009 Victory Drive were affected by the fire, officials reported. More than 100 firefighters were sent to the scene to extinguish the fire, AFD said.

Residents of all 24 units -- more than 30 people -- will be displaced, the Austin Fire Department said. Fire officials said they believe the cause of the fire to be accidental -- due to an improperly discarded cigarette on the second-floor. According to AFD, the leading cause of fires in Austin every year is improperly discarded smoking material and unattended cooking.

The Austin Fire Department shared drone video of the fire:

Officials said Wednesday the fire started on an exterior wooden balcony, then spread to the third floor and attic.

"Special thanks to the Ann Richards School for Young Women Leaders — who opened up their closed campus to the displaced residents, serving as a temporary shelter for the night — and to our brothers and sisters at the West Lake Fire Department, who sent two of their units to assist us at the scene," the fire department tweeted Tuesday.

The original alarm was sent out at 2:26 p.m., the second alarm was sent out at approximately 2:35 p.m. and the third was sent out at 2:49 p.m when the fire moved to the attic. When the fire moved to the attic, AFD said it had pulled firefighters from the building.

Austin ISD confirmed with KVUE that the Ann Richards School for Young Women Leaders, located on Prather Lane, was on a reverse evacuation. In a reverse evacuation, everyone stays inside, can't leave the building and no one can come in. Classes and school activity resumed as scheduled, according to AISD. Reverse evacuation does not mean a lockdown. Austin ISD said in a tweet that all children were safe at the Ann Richards Summer Camp and Little Stars Camp.

PHOTOS: Fire reported at a South Austin apartment complex