NANNING - Thirty people, including 23 children, were injured when a swarm of hornets attacked a primary school in South China's Guangxi Zhuang autonomous region, it was announced on Friday.

The attack happened around 10 am Thursday at Hongxing Primary School in the region's capital Nanning, said the school's headmaster Huang Dewang.

One teacher, 23 children aged between five and eight, and six villagers who came to help were injured. Among them, 29 were hospitalized and the other received treatment at home.

Most of them suffered stings in the head, neck, hands and feet, but their injuries were not life threatening, Huang said.

The teacher, Li Zhiqiang, said he was having a rest near the classroom when he heard children screaming that they were being chased by hornets .

Failing to drive the hornets away, Li told the children to hide under the tables. He stayed outside trying to drive off the insects before he passed out.

"Maybe because the hornets are poisonous, I just fell onto the ground and became unconscious," he said.

A hornets' nest was later found on a banyan tree 80 meters away from the attack spot, but it was unknown yet why the hornets attacked, he said.

Firefighters who came to help have cleared the nest, and are searching nearby for other nests.