TULSA, Oklahoma - A small fire in a classroom at Tulsa's Thoreau Demonstration Academy prompted a brief evacuation Wednesday morning.

Students and staff at the school located at 7370 East 71st Street were moved outdoors as firefighters searched the school.

Tulsa Public School spokesman Chris Payne says a fire started in a box in a lower level classroom that contained some tissue. It was extinguished quickly.  

Students with classes on the lower level were moved to the gym until firefighters were able to ventilate the building.

What sparked the fire remains under investigation.

Payne says no one was injured.