According to police the gunman fired multiple shots in the school at 10:33 a.m. Police have not said how many people were killed or wounded, but aerial video from the scene shows five bodies laid out under sheets on the school lawn.
Police described the suspect as an Asian male, 5-foot-9, wearing tan pants, according ABC station KGO-TV in San Francisco.
Although police have reportedly detained one person, it is unclear if that person was the gunman or if there was a continued threat on campus.
One witness described a chaotic scene in the moments after the shooting. Brian Snow was at a nearby credit union, when he first heard the shots and saw a victim run out of the building.
"I just heard more gunshots. A lady came out running and she had blood on her arm, but I didn't know how bad the wound was," Snow told KGO Radio. "She was just trying to make sure everyone was safe and took off her jacket and she had a big old hole in her arm."
Oikos University is a Christian university that focuses on nursing. The school's website describes students as "given the opportunity to obtain a Christian education that is based on solid Christian doctrine and ideology. Our main goal is to foster spiritual Christian leaders who abide by God's intentions and to expand God's nation through them."