YICHANG, March 20 -- At least another two kindergartens in central China's Hubei Province are being investigated in connection to the illegal feeding of antiviral drugs to children, local authorities said on Thursday.

The legal representative of Jinbei Kindergarten has been detained. All children attending the school can receive a free physical examination, according to a notice in front of the kindergarten's entrance gate.

Many parents said their children at the kindergarten in Wujiagang District in the city of Yichang told them that they were asked to eat "bitter tablets". But there has been no explanation from the kindergarten, according to parents.

Another kindergarten is also under police investigation. Police did not give details about the kindergarten.

On Tuesday, the principal and vice principal of Xingang Kindergarten in Yiling District of Yichang City were detained for illegally giving children anti-fever drugs.

Principal Li Xiujuan and vice principal Zhang Yubo both admitted to having fed pupils an over-the-counter anti-fever drug and vitamins to boost their immunity and improve attendance.

Under Chinese law, medical practitioners must have a license. If convicted, the accused could face more than 10 years in prison.