Iran is seeing its most vociferous outcry yet over the use of genetically-modified ingredients in food production.

Opponents of food products with GMOs have recently elicited fatwas from top clerics, declaring commercial sale and cultivation of genetically-altered crops “not permitted.”

Local media is at the center of the campaign, with Tasnim news agency on Sunday publishing a letter to state officials by a group of university professors, researchers and activists, urging a ban on the trade, growth and imports of GM food.

“It is many years since genetically-modified products entered the food chain in Iran without consumers’ knowledge. Credible information suggests that no tests have been carried out to evaluate the risks which such products might have,” the letter said.

It was addressed to parliament and ministries of health and agriculture, urging “more sensitivity to the hazards of GM products,” Tasnim reported.

Signatories warned of efforts by a group of GM food advocates who were after commercialization of GM rice, wheat, cotton, potatoes and sugar beet “under the guise of attaining self-sufficiency and preventing imports.”

Almost no food carries labels listing genetically-modified ingredients in Iran. Allegations of a rise in cancer cases and other diseases have fueled speculations that GM products could be a culprit among other causes.

Tasnim cited a warning by Grand Ayatollah Mohammad Alavi-Gorgani about health and security risks of genetically-manipulated products.

This undated photo shows Ayatollah Mohammad Alavi-Gorgani talking to Tasnim.

Israel, the senior cleric said, is behind the campaign to promote GM food. “May God help our beloved officials realize that this is one of the colonial ways,” Ayatollah Alavi-Gorgani said.

According to a fatwa by the cleric, “scientific research in the field of genetically-modified products has no problem but as long as their safety and harmlessness has not been scientifically verified, commercializing them is not permitted.”

Last year, Iran imported $5.5 billion of GM products, according to head of the Iranian Organic Association Ali Nourani who said the imports were threatening the health of consumers.

Nourani has said Iran’s move toward embracing genetically modified organisms (GMOs) makes no economic sense.

“The Iranian society is not starving to say we must move toward genetically modified products, which amounts to toying with the health of the people.”

Potato harvest at a farm in Kerman in southeast Iran

Across the world, opponents have cited a number of independent studies linking GMOs to a wide range of diseases and even possible environmental disasters.

In July, Russian media said the country had joined more than 30 countries, including China, banning the use of GMOs in food production under a bill signed by President Vladimir Putin.

The European Union has rigorous restrictions in place on GM cultivation in the 28-member bloc while countries such as France have banned the cultivation of genetically modified crops.

A variety of GM products, chiefly rice and cooking oil, is imported into Iran, however. Iran has also been dabbling with biotechnology for years, cloning its first sheep in 2006.

The first GM rice is already grown in Iran for human consumption. In May 2015, the first sample of Iran’s GM cotton was unveiled by Minister of Agriculture Mahmoud Hojjati.

According to Ali Karami, a specialist in medical biotechnology and genetic engineering, an “import mafia” is behind the distribution of GMO products in the country.

In February, he told Tasnim that imports of genetically modified products were a “Zionist plot” to infect Iranians, citing them a “serious example of infiltration.”