A former doctor with a history of mental illness hacked six children to death with a machete Tuesday and injured seven others at a primary school in southeast China, state media reported. The attacker was a middle-aged man who allegedly had mental problems and had been dismissed from his job at a community clinic, Xinhua news agency quoted the local government in the city of Nanping as saying. The man was arrested by police and the school was shut down following the attack which occurred early in the morning as pupils were arriving, it said. The injured children were being treated in hospital and were said to be in stable condition, the report said, without giving their ages or other details. Although crime rates have risen in China since it began opening up three decades ago, violent crime remains rare compared to Western countries. 