China has rejected 12 shipments of corn from the United States as they were found to contain a genetically modified variety not approved by Chinese agricultural authorities, the country's quality watchdog announced on Dec 20.

Entry and exit inspection and quarantine authorities in Fujian, Guangdong, Zhejiang and Shandong provinces have found a genetically modified variety, also known as MR 162, in 12 cargoes of shipments from the US totaling 54.5 metric tons as of Dec 19, the General Administration of Quality Supervision, Inspection and Quarantine said in a news statement.

The quality watchdog said it has urged the US to strengthen its quality control of corn shipment to "prevent the risks of genetic pollution to China".

The authority first found ingredients of the genetically modified variety in a cargo of corn in Shenzhen, Guangdong province.

According to a regulation on genetically modified products issued by the State Council in 2001, only GM products that have been on the market and proven to be free of hazards to human health and the environment can be imported to China.