BEIJING - Chinese authorities have vowed zero tolerance and harsh punishment for rule-violating sales and growing of genetically modified (GM) crops days after a media exposure of GM rice on sale at a supermarket in central China.

"The ministry will punish any companies or individuals that ignore regulations to grow or sell GM grains," the Ministry of Agriculture said Tuesday in a statement. "There will be no tolerance for those violating practices."

China Central Television (CCTV) found GM rice, which is not allowed to be commercialized in China, on sale in the supermarket in Wuhan, capital of Hubei Province, the broadcaster reported on Saturday.

CCTV commissioned tests on five packs of rice picked at random from the supermarket's shelves. Three were found to contain a GM variety.

CCTV also found that GM rice was being sold in Hunan, Anhui and Fujian provinces.