A man broke into a classroom in Yunxi county, Hubei province, and stabbed a teacher and eight students before jumping off the primary school building on Monday morning. Three students died on the spot and two suffered serious injuries.

The tragedy on the first day of the new school session is another warning to authorities to strengthen security in schools. The security system should be preemptive in nature, because no amount of material help and psychological counseling can ease children's trauma and bring relief to victims' families after a tragedy has taken place.

Similar attacks on schools and kindergartens, in which dozens of schoolchildren were killed, shocked the nation in 2010. Most of the men responsible for the mayhem later said they had attacked the children to avenge the "unfair treatment" they had got from society.

The tragedies prompted authorities to mobilize police, security guards, teachers and parents to strengthen security in and around schools, and establish an accountability system for school headmasters and headmistresses.