WUHAN, Sept. 2 -- The primary school where three students and one teacher were stabbed to death by an angry father has resumed operation Tuesday in central China's Hubei Province.

Medical staff have been sent to the Dongfang Primary School in Yunxi County to help the students and teachers get over the psychological trauma left by the incident, according local government.

The school has increased the number of safety guards and patrols around the campus. And visitors are being screened before entering the school.

The county government also set up a special task force to deal with the aftermath.

Chen Yanfu, 43, allegedly upset that his daughter was not allowed to register at the school, rampaged through classrooms on the fifth floor of the school's main building, stabbing students and teachers, at around 10:20 a.m. Monday, the first day of the new semester.

A teacher surnamed Liu and eight students were rushed to hospitals. Three pupils - two boys and a girl - died on the way. Liu later died in the hospital.

Another student was seriously injured in the chest. Four more students are in a stable condition.

Fu Qingyu, the school's headmaster, said Chen took his daughter to the school for registration on Sunday, but a teacher told him she had not completed her summer vacation assignment and asked him to ensure she finish it at home. There was no quarrel between the teacher and Chen on Sunday, he added.