The man stormed into Nguyen Du Secondary School in Tam Ky City on Tuesday, according to school principal Le Cong Thong. The incident stemmed from a conflict earlier that day, when two students allegedly beat the man's child during a football game. The boy called his father using the school's security guard's phone.
After taking his son to hospital for a check-up, the father returned to the school later that afternoon. He entered a classroom and physically assaulted the two students involved.
"The guard didn't have enough time to stop him," Thong said, noting that the situation was brought under control only after the intervention of guards and teachers.
The school has since scheduled a meeting with the parents of all three students and their homeroom teachers on Wednesday to discuss the incident. The father has apologized for his actions.
Local police and the Tam Ky Department of Education and Training have been notified about the assault.