Media reports say that none of the children suffered life-threatening injuries, but that two were seriously hurt in today's attack.
An official at Haikou's Longhu police station declined to give further details and said the case was under investigation.
Knife attacks against schoolchildren have become fewer in recent years after Chinese schools were hit by a rash of stabbings roughly five years ago. The attacks, mostly carried out by perpetrators with mental health issues, sparked outrage among Chinese parents who demanded enhanced security at schools.
In one of the deadliest cases, a 42-year-old man killed eight children at an elementary school in Fujian province in 2010.
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