MESA, AZ — Mesa fire crews are fighting a fire at an eight-unit apartment building near Dobson and Baseline roads.

Mesa Fire says the fire broke out around 1:54 a.m. Saturday.

When firefighters and Mesa police arrived, they found two adults and four children all suffering from serious burns, Mesa Fire says.

All six were taken to a local burn center, according to Mesa Fire.

Mesa Fire adds one of the children was first taken to Banner Desert Medical Center before being airlifted to a burn center for specialized care.

The fire was upgraded to a third-alarm response, with crews from Mesa, Tempe, and Chandler working together to battle the flames, Mesa Fire says.

About 30 residents were evacuated and taken to a nearby junior high school to get them out of the cold and provide support, according to Mesa Fire.

There’s no word yet on what caused the fire. Mesa Fire says the investigation is ongoing.