Three-year-old twins were released from the hospital Tuesday, a day after suffering injuries from a three-alarm apartment fire in Everett.

The girls were released to the custody of their mother, according to the Everett Fire Dept.

Monday's fire involved three units at the Olin Fields Apartments in the 10100 block of Holly Drive.

An Everett Fire Department assistant chief said an aunt was on her way to watch the children and showed up several minutes after the fire started.

A fire marshall driving nearby witnessed what is described as a "thermal column" and went directly to the apartment, helping knock on doors while neighbors called 911, according to the Everett Fire Department.

Firefighter teams found the girls in a back bedroom down the hallway. One was apparently on the bed and the other was between the bed and the wall.

At the time of this fire, Everett firefighters were already battling a fire at an automotive business downtown. That led to several other agencies coming to the aid of the apartment fire, including a U.S. Navy fire truck.

The cause of the fire is still under investigation.

One firefighter had a minor hand injury.

Update: Fire officials originally reported the twins were 2-years-old.