Since the end of March, when a mentally unstable former teacher killed eight children at a primary school, China has suffered a series of copycat knife attacks.

Several kindergartens have been broken into by male attackers, who have hacked at children with knives and hammers, sending Chinese parents across the country into panic.

On Tuesday, a spokesman for the Beijing Public Security bureau said police had prevented seven attempted copycat attacks on schools since the March incident. Schools across the country have been staffed with extra security and given pepper spray and restraining poles to use against assailants.