BEIJING -- A spokesperson for the State Food and Drug Administration (SFDA) said here Friday that nine drug retailers in Anshan City, northeast China's Liaoning Province, had been disqualified because they were found illegally trading dopes.

Yan Jiangying said that ranking SFDA officials led investigation teams to Beijing and the other cooperative host cities in the Chinese mainland for the 2008 Beijing Olympics, namely Shanghai, Tianjin, Shenyang, Qingdao and Qinhuangdao.

Shenzhen, an economically prosperous city bordering Hong Kong, was also on the list of investigation for illegal trades of dopes, Yan said.

The investigation teams overhauled local drug manufacturers and traders, signed responsibility contracts with them for banning producing or trading dopes, the spokeswoman said.

In addition, the food and drug authorities oversaw online information on dope-related trades, Yan said.