(CNN) -- Three California students were treated for minor injuries Wednesday after a firearm mounted on a police motorcycle discharged accidentally, police said.
Two of the students were taken to a hospital as precaution for what appeared to be minor injuries, the Chino Valley Unified School District said on its website.
The third student was released to parents after they signed an "against medical advice" form for the child, said Chino Valley Fire District spokeswoman Massiel Ladron De Guevara.
The motorcycle was on display at Newman Elementary in Chino as part of "Red Ribbon Week" activities promoting drug awareness, according to police and the school district.
Investigators were investigating the incident Wednesday, police said.
CNN's Artemis Moshtaghian contributed to this report.