Mexico has warned the United States against imposing a unilateral tax on Mexican imports to finance the border wall, saying it could respond in kind.
Mexican Foreign Minister Luis Videgaray said the government could place tariffs on selected goods from United States reliant on exports to Mexico.
Earlier, President Donald Trump vowed to start building the wall “soon, way ahead of schedule”.
The US government says it will start accepting design proposals next month.
The US Customs and Border Protection Agency has informed that it will ask companies to submit proposals “for the design and build of several prototype wall structures” on or around March 6.
A shortlist of the best designs will be drawn up by March 20, after which bidders will be asked to cost their ideas.
Contracts are expected to be awarded by mid-April.
Addressing the CPAC in Maryland on February 24, President Donald Trump vowed to always put American citizens first and build a “great, great border wall”.
The figure is much higher than Donald Trump’s estimated price tag of $12 billion.
President Trump has proposed to levy a 20% tax on Mexican imports to pay for a border wall.
In a radio interview on February 24, Luis Videgeray said that “Mexico believes in free trade”, but “would have to respond” if the US tried to fund a border wall by imposing a tax on Mexican imports.
“What we cannot do is remain with our arms crossed,” he said.
“Mexico will face this as a reality and not just as a rhetorical threat because we have realized that rhetorical threats come and go.”
According to reports, Luis Videgeray has previously identified states including Iowa, Texas and Wisconsin as possible targets for retaliatory tariffs.
Mexico is by far the top destination for Texan exports, with goods worth $92.4 billion exported there in 2015, according to the US Department of Commerce.
The wall is a sensitive political subject in Mexico. President Enrique Pena Nieto canceled a trip to meet President Trump last month over the dispute and has said Mexico will not fund the wall.
On February 23, Secretary of State Rex Tillerson and Homeland Security Secretary John Kelly met their Mexican counterparts in Mexico City.
Neither side made any mention of the wall in the news conference after their closed-door meetings.
President Donald Trump needs Congressional approval for funding before moving forward with construction of the wall.