Teachers and parents at a middle school in Gwangju have strongly protested a lack of action by school officials, who failed to report to authorities a recent violent outburst by a student wielding a knife.

According to the Gwangju branch of the Korean Teachers and Educational Worker's Union, 25 of the 27 teachers of the school submitted a petition to the Gwangju Metropolitan Office of Education on Tuesday calling for its principal and vice principal to be replaced.

"The principal did not do anything required of his duty for neither the students or the teachers who had to watch the outburst. ... No information had been shared to the teachers even after the police came to the school the next day," they claimed in the petition.

According to local media reports on Tuesday, the student had threatened an attack with a box-cutter knife at around 3 p.m. on June 27, but had been overpowered by his teacher and other students. No injuries occurred as result of the incident.

But teachers complained that the school did not take appropriate measures. It was later revealed that the case was not reported to the education authorities or the police.

The teacher who was threatened was required to work for the rest of the day, instead of being sent home immediately.

A parent of one of the students eventually reported the case to the police the next day, but the police said they were not conducting a criminal investigation as the threatened teacher did not want the student to be punished.

The school principal claimed that it was the teacher's decision not to involve the police, as the situation had already been wrapped up.

After the incident, the school had the student be homeschooled for the time being and commenced the process to have him transferred, while giving five days' paid leave to the teacher he threatened. Gwangju's education authorities designated the student, who was revealed to have learning disabilities, as a student in need of special education.

The punishment for the student will be decided at the GMO's disciplinary committee.