LANZHOU, Sept. 21 (Xinhua) -- The number of children hospitalized with food poisoning after eating school meals at a kindergarten in northwest China has risen to 307, a local official said on Friday.

The children were in stable conditions, said an official with the health bureau of Wuwei, Gansu Province.

The children at Shiyan Kindergarten in Wuwei City began to suffer vomiting, fever and stomachaches on Wednesday morning and dozens showed similar symptoms in the afternoon.

By 7 p.m. on Friday, a total of 307 children had been sent to four local hospitals in Wuwei, the official said.

The Wuwei government said Thursday in a statement that 260 children had been sent to two hospitals.

One teacher with the kindergarten said the children had porridge and buns for breakfast on Wednesday.

Police are investigating the incident.