A White House trade adviser and a leading Republican senator say a US plan to impose tariffs on Mexican goods might not go into effect.
Adviser Peter Navarro told CNN Donald Trump's threatened tariffs, due to come into force next week, might not be needed because the US now has "the Mexicans' attention" on stemming illegal immigration.
Frustrated by the lack of progress on a signature issue from his 2016 election campaign, Trump unexpectedly told Mexico last week to take a harder line on curbing illegal immigration or face five per cent tariffs on all its exports to the United States, rising to as much as 25 per cent later in the year.
Mexican officials will seek to persuade the White House in talks hosted by US Vice President Mike Pence that their government has done enough to stem immigration and avoid looming tariffs.
Pence is looking for a comprehensive suite of proposals from the visiting officials about stopping the flow of migrants from Central America, a White House official said.
"Trade and all other aspects of our relationship are critically important, but national security comes first and the White House is dead serious about moving forward with tariffs if nothing can be done to stem the flow of migrants," the official said, speaking on condition of anonymity.
"The vice president is eager to hear what tangible measures the Mexican government is prepared to take to immediately address this growing crisis," the official added.
Mexican President Andres Manuel Lopez Obrador said he was optimistic the talks can end in an agreement.
"We believe that these tariffs may not have to go into effect precisely because we have the Mexicans' attention," Navarro said.
Trump has faced significant resistance within his own Republican Party over the threatened tariffs, with many lawmakers concerned about the potential impact on cross-border trade and on US businesses and consumers.
Chuck Grassley, the Republican chairman of the US Senate Finance Committee, predicted that the United States and Mexico would strike a deal to avert the tariffs.
Mexican officials will offer a "long list of things" to avoid the duties in talks this week with their American counterparts, Grassley told reporters, adding that he thinks a possible deal could be announced on Thursday night.