TOKYO, Dec. 18 (Xinhua) -- A kindergarten in Kyoto Prefecture is under investigation after 133 children were mistakenly given cakes with plastic chocolate decorations to eat during a school activity, Japanese media reported on Thursday.

According to the reports, the incident occurred on Dec. 10 at Sanae Kindergarten in Yawata City. During a cake-making experience event, staff members mistakenly put plastic chocolate decorations used for making food models on top of the cakes and distributed them to children aged between 3 and 5.

Local authorities said that at least three children have since complained of stomach pain. While no serious injuries have been confirmed, officials are examining whether the symptoms are linked to the incident.

The Yawata City government described the matter as serious, citing concerns over the health and safety of young children, and has instructed the kindergarten to take concrete measures to prevent a recurrence. An investigation into how the mistake occurred is ongoing. Enditem