Banorte, HSBC and Santander all said on their Twitter accounts that the problem was with the company that was processing card payments, and that they were working on finding a solution.

Reuters witnesses in Mexico City said they had their cards declined at different stores and saw others that had put up signs informing customers that their payment systems were down. Twitter users outside the capital reported the same problems.

It was not immediately clear whether cards other than those issued by Banorte, HSBC and Santander were also affected. The Mexican Finance Ministry did not immediately reply to a request for comment.

The failure comes as the administration of President Andres Manuel Lopez Obrador is promoting the use of cards instead of cash in an attempt to clamp down on illicit cash and increase financial inclusion.