"We have to make our presence felt on campus so that students will be able to contact police on their way home or to school when necessary," said Zhan Wang, deputy chief of the Changbai police station in Shenyang.

Community police officer Lin Haichuan, who is the officer on duty at the Shenyang Railway No 5 Primary School, said that his workload has increased, but it is worthwhile.

"Because I am a father as well as a policeman, I completely understand that all parents want their children to be safe," he said.

In the past few years, the country has seen an increase in the number of violent crimes committed against students.

There were at least six attacks on children in or near schools and kindergartens in 2010, resulting in the deaths of a dozen students and the injury of many others, earlier reports said.

After these incidents, the Ministry of Public Security and the Ministry of Education ordered schools to provide security personnel and a surveillance system that is connected to public security facilities.

The Ministry of Public Security also ordered public security agencies at all levels to step up school security in line with local conditions.

Shenyang has been one of the nation's pioneers in school security. Beijing and Shenzhen, as well as Shandong and Sichuan provinces, have adopted similar measures since 2010.

But as the campaign in Shenyang only runs for nine months, many parents are worried about the future.

"I hope they (the police) can be stationed permanently here," said Ni Yuqin, vice-headmaster of the No 5 school.

However, sources close to the public security department said that community police officers have many duties and cannot be everywhere at all times.

Zhang Xiaodong, director of the youth rights protection office of the Liaoning provincial League Committee, said that "being aware is the most important lesson".

The most common safety problems include school violence, food poisoning, stampedes and fires.

"Never think that the school and children can be safe once police arrive. Many accidents occur because of the negligence of teachers and security personnel," he said.