A man ignited a can of gasoline in a primary school in central China on Monday morning, killing at least three students and injuring 14 others, a local official and state media said.

A 19-year-old villager in Gongyi, a city in Henan province, entered a room where 21 children were having classes, locked the door and set the room on fire, the official Xinhua News Agency said.

A local Communist Party official who would only give his surname Ma, said three 5-year-old children were killed and 13 others injured. A teacher was also hurt, he said.

Police were searching for the suspect, Bai Ningyang, Xinhua said, adding that the motive for the attack was not immediately clear.

In March, China announced it would start posting police at many schools throughout the country following a series of knife attacks on children, hostage-takings, fires and other accidents.

Most of the attacks were blamed on personal grudges or people with psychiatric problems.

Last October, a man opened fire with six homemade guns at a school yard in central China's Anhui province as students did their morning exercises, wounding 16 children and two adults.