XI'AN, March 14 -- Order has been restored at two kindergartens in northwest China's Shaanxi Province, which have been accused of administering antiviral drugs to children since 2008.

Xi'an city government has sent 171 child-care and teaching staff to work at Hongji Xincheng and Fengyun Lanwan kindergartens, which have a total of 1,455 children.

"Operations at the two kindergartens are back on track," an official with the city government's publicity office told Xinhua on Friday.

More than 200 children have received a free physical examination since Wednesday, while the city's education department has carried out safety examinations at all kindergartens and schools in Xi'an.

Police are investigating the sources of the prescription antiviral drugs, as well as the quantity and scale that has been in use.

It is suspected that the kindergartens bought the drugs under the name of a medical organization, according to the police.

The investigation has so far confirmed that the kindergartens gave children moroxydine ABOB to prevent cold and enhance resistance to improve their attendance, local officials said at a press conference on Thursday night.

Police detained two more suspects on Thursday, the deputy principal of Hongji Xincheng, surnamed Zhao, and the kindergarten's doctor. Both are suspected of illegal medical practice.

The private Fengyun kindergarten's legal representative, surnamed Sun, its principal, surnamed Zhao, and the kindergarten's doctor, surnamed Huang, were detained on Wednesday.

The investigation also found that the two kindergartens bought 54,600 moroxydine ABOB tablets on ten separate occasions from four medical wholesale companies from November 2008 to October 2013.

Children were given the medicine every spring and fall. Younger children were given half or one tablet per day, two days a week. Older children were given one tablet per day, three days a week.

The Xi'an government set up a joint team consisting of personnel from police, education, health and pharmaceutical supervision authorities after a parent on Sunday said in a microblog that the Fengyun Lanwan Kindergarten had been giving children the prescription medicine for years.

Dozens of parents on Tuesday gathered and blocked the road in front of the kindergarten demanding an explanation.

Some parents told Xinhua their children were experiencing discomfort with several symptoms, including dizziness, leg pain and stomachache.

Earlier, the Xi'an municipal government sent ten bottles of moroxydine ABOB tablets found in Fengyun kindergarten for further testing and ordered medical experts to conduct analysis and assessment of the drug's effects on humans.