A primary school teacher in Changsha, Hunan province has been suspended after he injured a student's forehead on Wednesday afternoon, according to local education authorities on Thursday.

The teacher, surnamed Song, injured a fourth-grade student during an after-school service organized by the school. The student was sent to the hospital, according to a notice issued by Changsha's Yuelu district education bureau on Thursday.

The teacher is under investigation by local police and the Party secretary of the school has also been suspended, the bureau said.

According to the Paper.cn, Song hit the nine-year-old girl in the forehead with a triangular ruler. The girl was sent to a hospital and underwent a five-hour craniotomy operation to remove skull fragments and another foreign object, the report said, adding that the girl is not yet in stable condition.