Mexican Foreign Minister Marcelo Ebrard said Monday that his country would reject a proposed solution to the immigration and tariff stand-off with the U.S. that would involve it keeping Central American asylum seekers.

The proposal, which has not been formally made by the U.S., would involve Mexico being designated a "safe third country" for the immigrants, meaning that refugees passing through Mexico to the U.S. would first have to claim asylum in Mexico. The U.S. has a similar agreement with Canada.

"An agreement about a safe third country would not be acceptable for Mexico,” Ebrard told reporters shortly before a meeting in Washington, D.C., with U.S. officials. “They have not yet proposed it to me. But it would not be acceptable and they know it.”

The president said Thursday he would place a 5% tariff on all Mexican goods, increasing 5% every month until the “illegal immigration problem is remedied.” The current crisis primarily involves people fleeing violence in Central America and passing through Mexico on their way to the U.S.

U.S.-Mexican talks to take place in Washington, D.C., were hastily arranged after the announcement.

Trump's threatened the tariffs came the same day that the Mexican Senate began the process to ratify the U.S.-Mexico-Canada Agreement on trade, a deal that would replace the 1993 North American Free Trade Agreement and is a top trade policy goal of the White House. While Thursday's announcement has not derailed consideration of the USMCA deal, Jesus Seade, Mexico’s deputy foreign minister for North America, warned that new tariffs could be a “stumbling block” regarding its passage.

Mexican officials added that imposing tariffs would do nothing to stop the flow of immigration and might even exacerbate it. "Tariffs, along with the decision to cancel aid programs to the northern Central American countries, could have a counterproductive effect and would not reduce migration flows,” Mexico’s ambassador to the United States, Martha Barcena, told reporters.