Chinese police have detained a kindergarten teacher who is accused of poisoning some 23 children in the country's eastern Jiaozuo city in Henan province, local media reported Monday.

The kindergarten students were taken to the hospital last week, when they began vomiting and fainting after breakfast, local media reports said, citing unnamed city officials.

Police said that the preliminary investigations found a high amount of sodium nitrite in the children's food, and they detained the teacher involved in the incident, who was identified only by the surname Wang.

One child remains in the hospital with "severe" symptoms, and seven others have been held for observation, China's Xinhua News Agency said, while 15 others were reported to have been discharged.

In 2002, some 42 citizens, most of whom were students, died in China's Nanjing after eating snacks in which mouse poison was later detected. The person convicted of putting the mouse poison in the snacks was executed.