BEIJING - Teachers reported the children, aged three to five, at the school in Lanzhou, the capital of Gansu province, suffered fever, diarrhoea, vomiting and stomach problems on Friday afternoon, the official Xinhua news agency said.

Forty of the 87 hospitalized children were well enough to be discharged from hospital by noon on Saturday, the report said.

Their illness appeared to be linked to yoghurt that the school served to the children, the report said. Disease control authorities were investigating the incident.