Fang Changchun, associate professor at the sociology department of Nanjing University, said this group needs a way to vent long-suppressed frustration, which the attackers in the five cases apparently did not find.
"They turned to children to express their resentment because they had no direct targets to do so, and compared to other places, schools and kindergartens are not as heavily guarded," he said.
But before such social problems are resolved, placing schools under police protection is necessary, he said.
Starting Thursday, many cities beefed up security measures.
Police in Changsha of Central China's Hunan province patrolled with sub-machine guns.
In Beijing, 800 well-trained security guards, clad in helmets and armed with tear gas and batons, made their presence felt in primary schools and kindergartens. The municipality aims to equip each school with at least two such security guards.
In Shanghai and Guangzhou, parents need passes to enter school.
Schools also started teaching children on how to respond to abductions or injuries, said Hu Zhijin, deputy principal of Zhenguang Primary School in Guangzhou.
"Though children feel restricted and some are a little afraid, the measures are necessary and reassuring," said an elderly man picking up his granddaughter at Huayang Primary School in Guangzhou.
Despite all the security measures, a woman in her 30s carrying a long knife was caught on Thursday by security guards and traffic police when she ran into a children's activity center in Hangzhou, Zhejiang province, local newspaper City Express reported.
No casualty was reported.Source: China Daily【1】 【2】