The alarming rise in youth violence is under the spotlight again as police investigate an assault involving teenage girls at Girrawheen Senior High School.
Police said the incident at the school on Friday afternoon allegedly involved three young females attacking a student outside a classroom.
Principal Rosalba Butterworth said the alleged victim told staff earlier she had heard rumours she would be "approached".
She said staff kept an eye on the victim throughout the day in an attempt to thwart problems and at one stage gave her individual tuition.
Staff also gave the teen emotional support but were unable to prevent the attack after the alleged perpetrators, who were not students at the school, entered the grounds without permission.
"Unfortunately, at 2pm the student went outside to meet another student and that is when the alleged incident with the three young people occurred," Ms Butterworth said.
"Teachers stepped in to help the student to safety and we set off our duress alarm and contacted police."
Ms Butterworth is in contact with the victim, who did not require hospital treatment.
"We work hard at our school to provide a welcoming, positive and supportive learning environment for our students," she said.
One parent, who would not be named, said the attack, which students saw, was sickening.
There have been increasing recent reports of youth violence, particularly involving girls.
This month, two teenage girls from Hedland Senior High School were filmed during a violent brawl.
Also this month, police charged a girl, 15, from Maddington with assault causing bodily harm for breaking the nose of a 17-year-old girl.
WA Council of State School Organisations president Kylie Catto said she was concerned about reported violence in schools but believed authorities were addressing the behavioural management of students.