Authorities are investigating an arson incident at Willow Glen High School in San Jose.
The fire happened overnight on Thursday when someone broke into a classroom on campus and started a fire in a wastebasket.
Security alarms went off and guards were able to extinguish the fire quickly.
The classroom where the fire happened sustained minor damage and it will remain closed for the day.
Authorities are treating the incident as arson.
Anyone with information is advised to contact Willow Glen High School at (408) 535-6330 or San Jose Police at (408) 277-8900.