Republican warning on Trump's Mexico tariffs: Don't do it

US Senate Majority Leader Mitch McConnell said there was little support for tariffs on Mexico among Republicans (AFP Photo/NICHOLAS KAMM)

Washington (AFP) - US Republicans including powerful allies of Donald Trump pushed back strongly Tuesday against the president's threat to slap tariffs on Mexican imports, warning the move did not have the backing of Congress.

Mexican and American officials were holding crunch talks in Washington on how to avoid the tariffs, which Trump said will go into effect on June 10 unless Mexico shows it is substantially reducing the flow of undocumented migrants to the southern US border.

At a lunch meeting between Republicans and White House officials, several lawmakers warned against Trump going full speed ahead.

"There is not much support in my conference for tariffs, that's for sure," said Senate Majority Leader Mitch McConnell after the lunch.

Asked if Trump's administration should be concerned about the threat of a disapproval vote to block the tariffs, Senator Ron Johnson told reporters: "If I were the White House I would be, sure. I made that point."

But McConnell sidestepped direct questions about whether his party would draft a measure to block Trump's tariffs from taking effect, a move that would trigger the most dramatic act of defiance from within the president's party since he took office in 2017.

"Apparently these (US-Mexico) talks are going well and I think our hope is that the tariffs will be avoided and we'll not have to answer any hypothetical," McConnell said.

Some Republicans did acknowledge, however, the prospect of a resolution of disapproval.

Senator Ted Cruz, a conservative Trump ally and fierce advocate for stronger action along the southern US border, said lawmakers expressed "deep concern and resistance to imposing tariffs on trade with Mexico because it will hurt American jobs."

In unusually forceful language against a Trump initiative, Cruz said he expressed his concerns "very directly" with the White House, saying tit-for-tat tariffs could cripple the Texas economy.

Senator Pat Toomey, a more moderate Republican from Pennsylvania, acknowledged the possibility of a legislative move to block Trump.

"I hope it doesn't come to that and we don't go down this road, but we'll see what happens if the president pulls that trigger," Toomey said.

Republicans delivered a stern rebuke of Trump in March, when they joined Democrats in overturning his declaration of a national emergency on the border.

Trump responded by issuing the first veto of his presidency.