BEIJING -- A former doctor armed with a large knife rampaged outside an elementary school in eastern China, stabbing eight young children to death and wounding five others Tuesday, a local official and a state news agency said.

The attacker launched his early morning attack as students were arriving for school. Zheng Minsheng, 41, had mingled with parents at the school gates then suddenly pulled out his knife and began slashing children, Xinhua News Agency said.

In the aftermath of the attack at the Nanping City Experimental Elementary School in Fujian province, doctors treated small children and bodies lay covered in bloody sheets. Police officers manned a cordon around the school. Some comforted distraught parents.

China has witnessed a series of school attacks in recent years, most blamed on people with personal grudges or suffering from mental illness, leading to calls for improved security.

Zheng was arrested after his rampage was finally stopped by passers-by and school security guards, Xinhua said, citing Wu Jiachong, the owner of a nearby shop.

Zheng worked as a doctor in a community clinic before resigning last June, Xinhua said, citing Huang Zhongping, spokesman for the Nanping city public security bureau.

Zheng was known to have a history of mental illness, said a man surnamed Wu in the Nanping city government office, who would not give his full name as is common among Chinese officials.

Eight children were killed, and five were being treated at a hospital, Wu said. Six died at the scene.

The victims’ ages were not known, but Chinese elementary schools typically have students ages 6 to 12.

The school was closed and students were sent home for the day.