It comes weeks after Mexican officials announced a deal with more than a dozen food makers and retailers, including Walmart, to halt rising food prices, with annual inflation in Latin America's second-largest economy hitting 8.76% in the first half of September.

Data from the country's statistics agency showed food, beverage and tobacco prices rose 13.27% year-on-year.

The plan aims to tame prices of basic food items and is set to waive certain regulatory requirements and taxes for signatories.

Nonetheless, aspects of the deal have sparked concerns from competitors and trade experts.

Walmart was not immediately available for comment.

The company represents 25% of Mexico's retail sales, Lopez Obrador wrote on Twitter.