Russia has suspended the import and use of an American GM corn following a study suggesting a link to breast cancer and organ damage.
Separately, the European Food Safety Authority(EFSA), has ordered its own review in to the research, which was conducted at a French university.
The decision by Russia could be followed by other nations in what would be a severe blow to the take-up of the controversial technology.
Historically, biotech companies have proved the safety of GM crops based on trials involving feeding rats for a period of 90 days.
However, experts at the University of Caen conducted an experiment running for the full lives of rats – two years.
The findings, which were peer reviewed by independent experts before being published in a respected scientific journal, found raised levels of breast cancer, liver and kidney damage.
The same trials also found evidence that consumption of minuscule amounts of a commonly used weedkiller, Roundup, was associated with a raised risk of cancer.
Both the GM corn, which carries the name NK603, and Roundup are the creation of US biotech company Monsanto.
The decision by the Russians to suspend authorisation for the American GM corn threatens to trigger a transatlantic commercial and diplomatic row.
Russia’s consumer rights watchdog, Rospotrebnadzor, said today that it has suspended the import and use of the Monsanto GM corn.
Rospotrebnadzor said the country’s Institute of Nutrition has been asked to assess the validity of the study.
It has also contacted the European Commission’s Directorate General for Health & Consumers to ask for the EU’s position on the corn’s safety.
Consumer scepticism in the UK and Europe means GM corn is not on supermarket shelves here, however it is fed to farm animals, including hens, pigs and dairy cows.
Last week Monsanto said it did not think the French study would affect its license to export the NK603 to Europe but would wait to hear from EFSA.