A Hong Kong school where a 13-year-old girl allegedly stabbed a classmate has said the teenager was previously in special care for being “unhappy”, but was never seen quarrelling with the victim beforehand.

The vice-principal of CCC Hoh Fuk Tong College in Tuen Mun said the wounded boy, accompanied by his father, was now in a stable condition, adding that a couple of pupils were absent due to the shock.

Recalling the incident, the vice-principal surnamed Leung said it took place at 3.35pm on Thursday, when the day’s lessons ended and the school held class-teacher sessions.

He said the girl sitting at the centre of the classroom suddenly attacked her classmate with a 30cm-long (12 inch) knife that she brought.

“When the teacher stopped her from doing so, the girl neither resisted nor hurt other students,” he said, admitting some students were frightened at the time and a few students did not come to school on Friday.

“We immediately evacuated the students in that class and we took the girl away from the scene. As the boy was wounded and bleeding, our teachers administered first aid treatment to him and the rescue personnel arrived after 10 to 20 minutes.”

The vice-principal said the girl had been “very quiet” but revealed she had been under special care as the school knew she had been “unhappy” and that police were investigating further details.

“She seldom speaks and has been extremely quiet all along,” he said, adding the school had not given her any demerits before and that she had not violated any rules.

The girl has been arrested on suspicion of wounding.

Police are currently investigating the case. Photo: Sun Yeung

He said the school arranged social workers, counselling teachers and education psychologists to help students, adding teachers separately briefed parents of the pupils in that class about what happened.

“The injured boy is now in a stable condition and mainly suffered from skin lesions and his right shoulder got some wounds,” he said.

Leung clarified there was no argument between the boy and the girl before the incident and that they did not even quarrel with each other during daily school life as some local media reported.

“There are no abnormalities before the incident,” he said, adding the school also had no previous record of the argument and scuffle between both since they were Form One classmates.

The vice-principal said the school could not know whether the stabbing was related to mental health issues, stressing police were investigating and medical staff was conducting a check-up. Some students were expected to give statements to police.

The Education Bureau said it was deeply concerned about the incident and had promptly contacted the school for information.

The school also said it had activated a crisis management team to follow up on the situation and would provide counselling services to students, parents and staff in need.