The Snohomish County Fire Marshal’s Office is investigating two small fires that were intentionally set early Thursday at Discovery Elementary School south of Everett in unincorporated Snohomish County, fire officials said.

Firefighters were called after an automatic fire alarm sounded at the school in the 11700 block of Meridian Avenue South around 3 a.m.

“They extinguished a small fire burning at a door on the southwest corner of the building,” Snohomish County Fire District 1 spokeswoman Leslie Hynes said. “The firefighters put the fire out before flames got inside the building. Damage to the door and adjacent wall and ceiling is estimated at $3,000.”

Firefighters said they also discovered someone had tried to set another fire outside a nearby portable classroom.

An arson investigation is being conducted by the Snohomish County Fire Marshal’s Office.

Anyone with information about the fires is asked to call investigators at 425-388-3557.