Top Mexican political figures are debating how to fight back against US president Donald Trump's aggressive stance on trade and immigration.
They have suggested the country could expel US law enforcement agents, stop detaining Central American migrants or no longer inspect north-bound lorries for drug shipments.
Some activist groups are also calling for a boycott of American brands.
Former president Felipe Calderon said "we have to design a policy of retaliation" for Mr Trump's proposed plans, which include making Mexico pay for the border wall he wants to build.
"We have to put US security issues under review ... including the presence of (US) agents" on Mexican soil, Mr Calderon said.
The comments came after current president Enrique Pena Nieto scrapped a planned meeting on Tuesday with Mr Trump after the American president tweeted that it would be better to cancel if Mexico was unwilling to pay for his proposed wall.
Ruben Aguilar, a political consultant who was spokesman for former president Vicente Fox, noted that Mexico had been stopping Central American migrants before they reached the US border "as part of the logic between two friendly countries".
He suggested that Mexico could say, "OK, I'm not going to stop Central Americans any more" and added: "Now if our two countries aren't friends any more, that is a card we could play to increase the pressure."
"Drugs are another" possible card, Mr Aguilar said, adding: "If you want to stop them with your wall, well we won't stop them any more, let them go through."
Mr Trump appeared to try to defuse the spat between the two countries on Friday, saying: "Great respect for Mexico, I love the Mexican people.
"We have really, I think, a very good relationship, the president and I, and we had a talk that lasted for about an hour this morning, and we are going to be working on a fair relationship."
The office of the Mexican president confirmed the call, calling it "constructive and productive", but did not specifically mention the wall or other policies proposed by Mr Trump.
Mr Pena Nieto's government instead stressed "the need for both countries to continue working together to stop the trafficking of drugs and the flow of illegal weapons".
"Both presidents recognised their clear and very public differences on this very sensitive issue, and agreed to solve those differences as part of an integrated discussion of all aspects of the bilateral relationship," Mr Pena Nieto's office said.
"The two presidents also agreed, for the moment, to no longer speak publicly about this controversial topic."
Mr Pena Nieto met Mexican politicians to discuss US relations.
"There will be constant communication between the federal executive and the Senate to define what actions to take," said Fernando Herrera of the conservative National Action Party.
Business magnate Carlos Slim called for "national unity" in the face of Mr Trump's hostility and said the country should have a measured response "without getting angry but without surrendering".
He called for a "modern, not protectionist" national programme of substituting imported products, the vast majority of which come from the United States, but stopped short of calling for a boycott of American goods.
"I think it is an error to think about boycotting companies," Mr Slim said. "What we should do instead is buy what is produced in Mexico."
A coalition of Mexican farm and consumer groups, however, did call for such a boycott when it raised the battle flag on January 18, two days before Mr Trump took office.
The campaign's slogan, "Consumers cry war!" echoes the first line of Mexico's national anthem as it calls on citizens to buy national products.
In a country where US chain restaurants, coffee shops and stores are now ubiquitous, social media users created long strings of hashtags such as #AdiosStarbucks #AdiosCostco, #AdiosWalmart, #AdiosMcDonalds, #AdiosProductosGringos , #ConsumoProductosMexicanos.
Peter Schechter, senior vice president for strategic initiatives at the Atlantic Council, said the dispute may awaken underlying currents of resentment in Mexico.
The US took away almost half of Mexico's territory in the 1848 Mexican-American War, though that historic resentment had faded in the last three decades.
"All this does is to solidify the view that an attempt to negotiate with the United States under this administration is impossible and that we should break from the United States," Mr Schechter said.
"This argument has moved from incredulous, to possible in people's minds. The next step is it moves from possible, to the right thing, and that step is not that far."
In a Washington Post opinion piece, former Mexican president Ernesto Zedillo said "the prudent thing" was to assume that Mr Trump would kill the North American Free Trade Agreement (NAFTA), which he said would be costly to Mexico.
"But such an outcome should not be cause for despair in my country," he wrote, calling for Mexico to reinforce its commitment to openness and tell companies from around the world that it remained open for business.
"The end of Nafta, as disruptive and costly as it would be in the short term, could be compensated for with the right set of policies," Mr Zedillo wrote.