A man with a knife has wounded 22 children - at least two of them seriously - and an adult at a primary school in central China.

The attack happened at the gate of a school in Chenpeng village in Henan province.

Police arrested a 36-year-old local man at the scene.

Security at China's schools has been increased in recent years following a spate of similar knife attacks in which nearly 20 children have been killed.

The BBC's John Sudworth in Shanghai says many of the attackers have been mentally disturbed men, prompting a debate about the effects of China's recent, rapid social change and the inability of an antiquated hospital system to cope with rising levels of mental illness.

The Associated Press news agency quotes a police officer as saying that this latest attack happened as pupils were arriving for classes.

The agency also quotes a county hospital administrator as saying that the man first attacked an elderly woman, then the children, before being overpowered by security guards.

He added that two of the injured pupils had been transferred to better-equipped hospitals outside the county.