The district says an assault on a student at Island High School prompted several campuses to shelter in place.
"A student was approached by a suspect armed with a knife in the school bathroom, said police in a statement. "A brief struggle ensued before the suspect fled."
The suspect was described as a white male in his 20s who was about 5'8" tall with a thin build, said police. He was last seen wearing a blue shirt and blue sweatpants.
Police say the student suffered a minor injury. The incident happened around 8:45am.
The district says it's important to know that "all students and staff at the other schools are safe." Alameda Police is investigating the situation, they are asking witnesses to come forward.
Update: @AlamedaPD has issued an "all clear" for our school sites, and we have lifted the shelter in place at our campuses. The schools are now returning to their regular schedules and activities. Thank you, students and staff, for following our emergency procedures so well!— Alameda Unified (@AUSDNews) February 8, 2019