The Ministry of Health has sent a team of medical specialists to Cixi , in Zhejiang province , to investigate why at least 233 children at a kindergarten developed abdominal problems.

The children, aged three to eight and who attended the Cixi Kindergarten for Sports and Arts, were all diagnosed as having enlarged intestinal lymph nodes.

Xinhua reported that their parents suspected cooking oil was to blame for the abnormalities. But earlier this week Cixi authorities dismissed claims that the oil was substandard.