OLATHE, Kan. (AP) — A suburban Kansas City high school principal is urging parents to speak to their children about tolerance after several incidents of racial harassment between students.

The Kansas City Star reports that Olathe North High School Principal Jason Herman informed parents of the problem Wednesday in a letter. He indicated that many of the incidents occurred on social media.

He said the behavior is “intolerable” and would be “swiftly” handled by administration. He said parents should speak to their children “about the importance of respecting everyone and our intolerance for any type of harassment.”

He also wrote that he had shared a similar message with students in an address he read in person.