BEIJING (AFP) - A farmer with mental health problems killed six people, two of them children, with an axe as they made their way to a kindergarten in China Wednesday, the local government and media reports said.

The incident is the latest in a series of violent assaults on children involving people with suspected psychiatric problems in China, which experts have blamed on rapid social change as the country's economy booms.

The 30-year-old attacker carried out the deadly assault in Henan province's Gongyi city, in central China, early Wednesday morning, the city government said in a statement.

One child and three adults were killed on the spot, while the other child and one more adult died of their injuries in hospital, Gongyi local authorities said in a statement.

"According to locals, the suspect Wang Hongbin has a history of mental health illness," it said.

A report on local news website www.dahe.cn said the adult victims were all parents taking their children to a kindergarten not far away.

An employee at the Tongxing Kindergarten in Gongyi, who would not give her name, confirmed to AFP that the two children were pupils at the establishment, adding the attack had not happened at the preschool itself but on the street.

She refused to comment further and hung up the phone.

An employee at a dog centre in Gongyi, surnamed Wang, told AFP the incident happened near a crossroads, close to a supermarket, and the area had been cordoned off by police.

Chinese authorities have been forced to increase security around schools after a series of violent assaults involving children. In many cases, the attackers were suspected of having mental health issues.

At the end of August, eight pupils were hurt when a staff member at a day care centre for migrant workers' children in Shanghai went on a stabbing spree.

The female worker used a box cutter to slash at children aged between three and four years old at the "Little Happiness Star" nursery in an eastern suburb of the metropolis, according to local news reports.

The suspect in that case was also believed to have suffered from mental health problems.

Last year, 17 people -- 15 of them children -- were killed and more than 80 wounded in at least five major attacks at schools in China.

Two of the attackers were executed and two others committed suicide. The suspect in the fifth attack was sentenced to death in June 2010.

Experts say that the assaults show that China is paying the price for focusing on more than 30 years of economic growth while ignoring problems linked to rapid social change.

Studies have described a rise in the prevalence of mental disorders in China, some of them linked to stress as the pace of life becomes faster and socialist support systems wither.