President Donald Trump on Saturday threatened duties of 30% on products from Mexico and the European Union, two of America’s biggest trading partners, in an ongoing tariff campaign that’s upended global trade since he retook office in January.

President Donald Trump has announced he’s levying tariffs of 30% against the European Union and Mexico starting Aug. 1.

The US is imposing a 17% tariff on most tomatoes imported from Mexico with immediate effect, the government said. The duty came into force after the US withdrew from a long-standing agreement with its southern neighbour,

President Donald Trump expanded his tariff threats over the weekend, calling for 30% levies on two of America’s largest trading partners: the European Union and Mexico.

While Mexico was spared from Trump's so-called "Liberation Day" tariff rollout on April 2, the 30% rate for the E.U. is 10 percentage points higher than what the president said he would apply to America's largest trading partner in April but lower than his mid-May threat of 50%.

CNBC's Megan Casella reports on President Trump's tariff announcement on Mexico and the European Union, set to take effect August 1.

Mexican President Claudia Sheinbaum on Tuesday said Mexico will take action if an agreement with Washington regarding new tariffs is not reached by the August 1 deadline set by her U.S. counterpart Donald Trump.

President Donald Trump posted letters to the leaders of Mexico and the European Union, saying they had not done enough to head off the new tariffs.

America’s biggest trading partners have tried tactics ranging from appeasement to retaliation to avoid higher tariffs. All find themselves faced with similar threats from Washington.