Police and education authorities in Beijing are probing a child abuse case at the Xintiandi branch of RYB Education Kindergarten, a well-known chain of preschools.
This is the latest in a number of similar cases reported recently nationwide.
Several parents reported to police on Wednesday night that their children, all around 3 years old and enrolled at the company's Xintiandi branch, had needle marks on their bodies and were repeatedly fed unidentified white pills.
Police were investigating and collecting evidence.
Doctors and forensic experts also are participating, but so far no conclusion could be made, according to the Beijing Municipal Public Security Bureau.
The education commission of Beijing's Chaoyang district, which oversees the kindergarten, said that it also is looking into the case and that three teachers have been suspended.
The Ministry of Education has begun a special inspection of the management of kindergartens nationwide and required local education authorities to take effective measures to improve teachers' morality and tighten supervision, according to a ministry release late Thursday.
RYB Education Kindergarten was China's largest early years education service provider in annual revenue last year, according to the Frost & Sullivan Report.
On Sept 27, RYB Education Inc, the kindergartens' parent company, rang the opening bell on the New York Stock Exchange, indicating it was the first independent enterprise to be listed in the early childhood education field. It's initial public offering was filed the day before.
RYB's stock price on the NYSE fell on Wednesday to US$26.71 a share, down by US$1.02, or 3.68 per cent.
The NYSE was closed on Thursday for a national holiday.
This has been the third reported child abuse case in a month. On Nov 13, Shanghai police detained a person surnamed Zheng who was in charge of a day care centre where staff were caught on camera abusing toddlers. Three other staffers were detained, according to Shanghai police.
Almost at the same time, Golden Cradle Education and Technology Group, which has more than 700 kindergartens and schools nationwide, also became involved in a similar accusation as parents said teachers at one of its kindergartens in Beijing abused children. Police are investigating, but so far no details have been released.