GUANGZHOU - Dozens of teachers at a Lufeng county high school in South China's Guangdong province continued their strike on Tuesday to protest violence against teachers.

The strike at Jiazi No 1 High School began on Monday after Fan Bing, a teacher at the school, was beaten twice by his students and their relatives last Friday.

Fan, 31, has been teaching at the school for eight years.

The teacher was first beaten by three male students after he tried to stop the students from disturbing a test last Friday.

The beating lasted about five minutes and was stopped by Fan's colleagues. But five minutes later, one of the three students called in his uncle, who then beat Fan until he lost consciousness and went into a coma.

Fan has come out of the coma but remained hospitalized on Tuesday in Rongjun Hospital of Guangzhou.

Doctors said they do not know whether Fan's left eye can be saved, as it was seriously damaged in the assault.

Police said the assailant, who escaped after he beat Fan, has a previous criminal record and was receiving medical treatment on bail.

From his hospital bed, Fan said he would forgive the students and their relatives if they apologized. So far none of them have apologized.

The case has again raised great concern among local residents over school security.

Lin Shaokui, director of Lufeng county bureau of education, and Chen Yukeng, chief of the county's public security bureau, have both called for a quick investigation into the case. They promised to bring the assailants to justice and seriously punish them.

Liang Weifa, director of Guangdong provincial department of public security, has also urged relevant departments to investigate the case and capture the suspect as soon as possible to ensure campus safety.

Ge Xinbin, a professor from Guangzhou-based South China Normal University, said teachers have the right to use proper ways to educate and criticize misbehaving students according to relevant laws and regulations.

"But the teaching environment now has become poorer compared to previous years and many teachers now dare not criticize their students in fear of retaliation," Ge said.

Ge urged relevant departments to introduce effective and concrete measures to protect teachers' personal safety, while ensuring the students' right to receive an education.

A teacher from Jiazi No 1 High School said Fan's case is not the first time that teachers have been beaten by students or their parents in Lufeng county in recent years. But none of the teachers' assailants have been punished so far.

"The school always makes concessions to avoid trouble, as most of the parents who dare to beat teachers have strong backing or a big network in the county," said a teacher, surnamed Chen.

Schools should not make concessions to avoid troubles after teachers' safety is damaged or threatened, Ge said.

In 2008, a teacher surnamed Huang had to stay in a hospital for two months after he was beaten by parents of his students in Damao Primary School.

Huang was beaten after the parents refused to pay the school's tuition and other fees.

Chen Chaozong, a teacher from Lufeng's Jiebei High School, was beaten by the parents of a male student in 2008 because Chen brought the student, who was creating a disturbance during class, to his office for reprimands.

Teachers in Lufeng's Jiazi No 3 High School and Jiaxi Primary School have also reportedly been beaten by parents of their students in previous years.