A man stabbed 22 primary school students in a knife attack in China on Friday, officials said, the latest in a series of assaults. The attacker "has been detained", said a spokesman for the Guangshan county government in the central province of Henan, where the stabbing happened. "Twenty-two elementary school students were stabbed, so was an adult villager" but none of the victims died, the official, who declined to give his name, told AFP. The state-run China News Service said a man attacked the students with a knife outside an elementary school, resulting in injuries which were "not life threatening". It did not give the children's exact ages. China has seen several violent attacks against children over the past two years, including a spate of five incidents in 2010 which killed 15 children and two adults and wounded more than 80. The assaults have forced authorities to increase security around schools and led to calls for more research into their root causes. Violent crime has been on the rise in China in recent decades as the nation's economy has boomed and the gap between rich and poor has expanded rapidly. Studies have also described a rise in the prevalence of mental disorders, some of them linked to stress as the pace of life becomes faster and socialist support systems wither. But authorities say that murder, which carries the death penalty, remains far less common than in most Western countries.