The Gauteng education department says a Soweto pupil, who threw a stone at a teacher and caused minor injuries, cannot be suspended.
The incident occurred at Albertina Sisulu Special School when a Commonwealth ambassador arrived to donate wheelchairs.
According to the department, the pupil became angry after the teacher attempted to discipline him in the school hall during the event.
In a video of the incident, the teenager could be seen chasing the teacher out of the hall. The teacher ran away, while other pupils and teachers tried to stop the pupil.
A teacher could be heard asking what his problem was.
He replied: "I have been patient with him for too long. Today, he will k*k himself."
Education department spokesperson Steve Mabona said that, while the school was instituting disciplinary processes against the pupil, he would not be suspended because of the "nature of his behavioural disability".
"[He] is still allowed at school and due to the nature of his behavioural disability, cannot be suspended. We are facilitating a diversion programme for the learner to address his behavioural challenges," he said.
Mabona added that the teacher has returned to the school.
He added that a psycho-social support team had been dispatched to the school to counsel all those affected by the incident.
Having seen an increased number of such incidents in Gauteng schools, Mabona said the department implemented several programmes to assist.
Some of the programmes included parenting workshops, aimed at strengthening parent/guardian involvement in supervising homework and instilling pupil discipline in and outside the school environment. He said the department has also partnered with social development, community safety and related NGOs to assist them in dealing with social ills in schools.