Michael Bowman contributed to this report.
Mexico warned Monday that President Donald Trump's threatened new tariff on its exports to the United States would hurt both countries' economies and cause even more Central American migrants to travel through Mexico to reach the United States.
At the start of talks in Washington, Mexican officials said they could only go so far in meeting Trump's demand to block migrants' passage through Mexico to avert Trump's imposition of a 5% tariff next week. The officials specifically ruled out a "third safe country" agreement requiring U.S. asylum-seekers to first apply for refuge in Mexico.
"There is a clear limit to what we can negotiate, and the limit is Mexican dignity," Mexico's ambassador to the United States, Martha Barcena, said.
Barcena added that U.S. tariffs "could cause financial and economic instability," reducing Mexico's capacity to address the flow of migrants and "offer alternatives" to people fleeing Guatemala, Honduras and El Salvador.
Mexican officials contended that an additional quarter million migrants could try to reach the U.S. if the tariff is imposed, on top of the tens of thousands already reaching the southern U.S. border each month.
Trump showed no sign of softening his demand as he tweeted during a visit to London.
Mexican President Andres Manuel Lopez Obrador remained confident the two sides would reach an agreement, telling reporters Monday that he was optimistic.
He said his government would not engage in confrontation, and would always defend those who migrate out of necessity due to violence or a lack of food or job opportunities. He also remained positive that no matter what happens in the dispute with the United States, Mexico has "exception, extraordinary," people and can push through any adversity.
U.S. Secretary of State Mike Pompeo and Mexican Foreign Relations Secretary Marcelo Ebrard are due to hold further talks about the dispute on Wednesday.
U.S. lawmakers returning to Washington after a weeklong congressional recess sharply criticized Trump's latest tariff tactic aimed at a major U.S. trading partner.
"This (tariffs) is not a popular concept," Republican Sen. John Cornyn said of public opinion in Texas, which he represents. "Mexico is our biggest export market."
Another Republican, Missouri Sen. Roy Blunt, expressed concerns that trade friction could harm a newly negotiated free trade pact between the United States, Mexico and Canada.
"I'm not a big advocate of tariffs, and I'd like to get the USMCA agreement approved," Blunt told VOA. "I don't see how the addition of a tariff (on Mexican goods) right now helps make that happen."
"Mexico is a critical trading partner of the United States," Democratic Sen. Ben Cardin of Maryland said. "You put up barriers, it's going to end up costing us jobs, and it's going to cost consumers."
Cardin added that Trump's threatened tariff "would be counterproductive," as far as boosting U.S. border security.
"If we need cooperation on the southern border, they (Mexican officials) are not going to give us cooperation. Why bother if we're going to have an antagonistic relationship?" Cardin said.