Police in China are hunting for a teacher who launched a violent assault on four school children in his office.

The art teacher at the school in Ankang in Shaanxi province, named as Lei Mingxing, reportedly beat one child so badly he fractured his skull.

The pupils were rushed to hospital after being found by another member of staff, terrified, cowering in a classroom and covered in blood.

The children are among only 22 who attend the school. The eldest of the children is just seven.

Describing the scene, head teacher Wang Qin said: "I walked past his office and heard crying. As I went in I saw the pupils on the floor, very distressed and covered in blood. We've no idea what's behind this.

"He has always been a very good teacher. We are a very small school, only 22 pupils, so this is totally shocking.

"He has been a good teacher for many years and has never shown any sign of violence before. We are very concerned for the children and will be talking to all of them to see what was behind this."

Investigators believe Mingxing fled on his moped and is now hiding in woodlands outside the city.

Police chief Deng Mingshan said: "We have found tyre tracks, footprints and empty wine bottles. We have surrounded the woods. We have spoken to the pupils and they say they have no idea why he did it. He just called them into his office and began attacking them."