Two adults were also injured in the attack Friday in Hanzhong. State broadcaster CCTV said the suspect was a 58-year-old man who apparently wanted to take "revenge against society" after being prosecuted for theft.
Photos posted by state media on Chinese social media show a child being carried on a stretcher.
The local public security bureau and propaganda department did not answer phone calls Friday.
Mass attackers in China often use knives or homemade explosives because Chinese law tightly restricts the sale and possession of firearms.
Knife-wielding attacker injures 7 children in China
25 November 2016
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An assailant wielding a knife has injured seven children outside a primary school in northern China.
