A White House trade adviser and a leading Republican senator said on Wednesday that a U.S. plan to impose tariffs on Mexican goods might not go into effect, offering hope for Mexico and American businesses concerned about economic damage from a new front in President Donald Trump's trade wars.

Adviser Peter Navarro told CNN that Trump's threatened tariffs, due to come into force next week, might not be needed because the United States 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 5 percent tariffs on all its exports to the United States, rising to as much as 25 percent later in the year.