Three children suffered minor injuries after their 9-year-old classmate shot them with a BB gun at an elementary school in Pasadena, officials said Friday.

The boy brought the air gun to Washington Elementary STEM Magnet and shot three classmates between ages 9 and 12 at the playground on Thursday morning, Pasadena police Lt. Kim Smith said.

The three were not seriously hurt, the lieutenant said.

Officers spoke with the 9-year-old boy, who was never arrested, Smith noted. She said the department will pass along the case to the District Attorney’s Office.

The child’s motive was unclear, Smith added.

The Pasadena Unified School District said it has launched an investigation into the incident and is cooperating with police, who have “increased visibility around the campus.”

Counselors are also available to students, and the school is “implementing an enhanced awareness of safety by both students and staff, and encourage everyone that if they see something to say something to an adult on campus immediately,” a statement from the School District said.

“The student will be subject to appropriate discipline,” the statement noted.

The incident happened the day when officials said a 16-year-old student brought a .45-caliber semi-automatic pistol to a high school in Santa Clarita, killing two of his classmates and injuring three others.

KTLA’s Alexis Lewis contributed to this report. 

Correction: A previous version of this story provided an incorrect day for when the Pasadena incident happened. This post has been updated.