A middle school teacher from Hefei, Anhui province, was suspended and given an administrative warning after being videotaped slapping 38 students in the face, according to the local education authority.

The teacher has apologized to the victims and their families, but the local education bureau and the provincial education department are still investigating.

On Sept 1, a student in a Grade 8 class in suburban Changfeng county secretly filmed the scene where his teacher, Zhang Haitao, stood at the front of the class and slapped the students in the face one by one when they failed to recite some ancient poems as required. The video went viral online soon after.

Most students' parents refused to accept the teacher's apology.

"My granddaughter, who was slapped by the teacher, is too young to dare tell me about her terrifying experience," said Sun Suying, a grandmother of one of the students. "When I heard about it and asked her to open her mouth, I saw her teeth bleeding."

One student in Zhang's class said he was frightened that day and was ashamed to be slapped in front of the class.

Zhang once taught in a middle school in a rural area and was known for his good teaching performance. He started teaching at the middle school in Changfeng this fall.

Sun Tao, the school's principal, said he was shocked to learn about the slapping.

"Zhang has many years of teaching experience. He should have known this was unacceptable," Sun said.

Gao Yucun, a teacher from Changfeng county, said the county's education bureau stresses every year that such punishments are prohibited.

"In any case, the personality of adolescents is significantly impacted by their teachers' behavior," said Yan Wansen, associate professor at the Chinese Academy of Sciences' Institute of Psychology.

"Any impetuous action or violence may harm students' mental health. Being slapped in public is definitely an abuse and may even lead to melancholia, which may need counseling and psychotherapy to relieve the psychic trauma."

Cao Chen and Zhu Lixin contributed to this story.