The duties, set at 17.09%, come after Washington moved to terminate a 2019 agreement that staved off such charges.

“Mexico remains one of our greatest allies, but for far too long our farmers have been crushed by unfair trade practices that undercut pricing on produce like tomatoes. That ends today,” commerce secretary Howard Lutnick said in a statement.

“This rule change is in line with President (Donald) Trump’s trade policies and approach with Mexico,” he said.

Mexico is a dominant supplier of US fresh tomato imports, and the commerce department said that antidumping duties are calculated to measure the percentage by which Mexican tomatoes were sold in the country at “unfair prices”.

The US had announced it was withdrawing from the tomato agreement in April, arguing that the action was meant to help American tomato growers compete fairly.

But observers have expressed concern that the duties could cause a spike in tomato prices.

On Monday, the Mexican government said it was working with tomato producers to limit the effects of the 17% duty.

“We are working together to minimise the impact,” said Mexican President Claudia Sheinbaum at her regular morning press conference, without details.

The antidumping duties are the latest blow to trade after Trump this year introduced wide-ranging tariffs on trading partners including Mexico.

After returning to the White House in January, Trump swiftly targeted Mexican goods with a 25% tariff – although he eventually exempted products covered by the US-Mexico-Canada free trade agreement signed during his first term.

Over the weekend, Trump threatened to raise the levy to 30% on Aug 1, as he pushes for a renegotiation of the trade relationship.

Mexico is one of the economies most vulnerable to US tariffs and duties, with 80% of its exports destined for its northern neighbour – which is also its largest trading partner.