Mexico's government published a decree on Monday to revoke authorizations and permits to import, produce, distribute and use the herbicide glyphosate and genetically modified (GM) corn in the midst of trade tensions with the United States, its biggest supplier.

Mexico will not grant new authorizations for GM corn for human consumption, the decree said. Health authority COFEPRIS, however, may grant authorizations for GM corn to be used as animal feed or industrial use for human food until a substitute is achieved.

The decree, which stated that it will go into effect on Tuesday, said it is in accordance with Mexico’s food self-sufficiency policies and protection of the health of the population and the environment.

Mexican President Andres Manuel Lopez Obrador’s push to ban genetically modified corn has been a major source of tension with the United States. Mexico is one of the biggest buyers of U.S. corn, with American farmers sending about 17 million tonnes of mostly GM yellow corn to Mexico annually, the majority of which is used for animal feed.

The new decree said COFEPRIS will conduct scientific studies with its counterparts from other countries to investigate the health impacts of consuming GM corn.

The new U.S. agriculture trade chief last week told Reuters that he had given Mexico until Feb. 14 to respond to a request to explain the science behind Mexico’s planned bans on GM corn and glyphosate.