"We made it clear today that if this issue is not resolved, we will consider all options, including taking formal steps to enforce our rights under the U.S.-Mexico-Canada Agreement," the USTR office said in a statement.

U.S. officials traveled to Mexico to discuss Mexico's approach to agricultural biotech products.

Representatives for Mexico's agriculture and economy ministries did not immediately respond to a request for comment. 

The countries have been at loggerheads over a Mexican decree, issued in 2020, that would have phased out imports of genetically modified corn and the herbicide glyphosate by 2024.

Mexico decided to postpone its ban of genetically modified (GMO) corn purchases from the United States until 2025 and that was deemed satisfactory by the U.S. government, Agriculture Minister Victor Villalobos said last month.

"Mexico's proposed approach, which is not grounded in science, still threatens to disrupt billions of dollars in bilateral agricultural trade, cause serious economic harm to U.S. farmers and Mexican livestock producers, and stifle important innovations needed to help producers respond to pressing climate and food security challenges," the USTR office said after the meetings on Monday.

Mexico is one of the biggest buyers of U.S. corn with American farmers sending about 17 million tonnes of corn to Mexico annually.

U.S. farmers were particularly concerned about the threat of a ban on GMO yellow corn for animal feed.

Mexico and its northern neighbors are already in dispute resolution talks over Mexican President Andres Manuel Lopez Obrador's energy policies, which the United States argues violate the U.S.-Mexico-Canada trade pact.

Earlier this month, President Joe Biden and his Mexican counterpart discussed having stronger economic ties, fighting illegal drug trade, and approaches to curbing illegal migration at a meeting in Mexico City.

(Reporting by Kanishka Singh in Washington and Tom Polansek in Chicago, additional reporting by Cassandra Garrison in Mexico City; Editing by Himani Sarkar)

By Kanishka Singh and Tom Polansek