"Other trading partners observing these threats will have the same mistrust of the negotiation process," experts argue.

The EU says the U.S. is resisting efforts to strike a trade deal and warned of countermeasures if no agreement is reached with U.S. by Aug. 1.

EU trade ministers have agreed that U.S. President Donald Trump’s 30% tariffs announced on the European Union are “absolutely unacceptable,” and they are studying a new set of countermeasures to respond to the move.

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%.

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 Trump announced on social media that he is levying 30% tariffs against Mexico and the European Union. They are set to begin on Aug. 1.

President Donald Trump has posted two new letters on his social media platform announcing tariffs on the European Union and Mexico.

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.

S&P 500 futures lost 0.5%, while Nasdaq 100 futures dropped 0.6%. Futures for the Dow Jones Industrial Average fell 204 points, or 0.5%.