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% higher than what the president said he would apply to America's largest trading partner in April.

The deadline for the duties to go into effect are still three weeks, which may mean the announcements could be a negotiating move.

The 30% tariff, announced by President Trump, will begin on August 1. Newsom Signals Major Increase in Electricity Costs Alligator crosses pedestrian walkway in South Carolina

Mexico did not face a new tariff on April 2, the day of Trump's so-called "Liberation Day" tariff rollout. There remains a 25% tariff on non-USMCA-compliant goods from Canada and Mexico, as well as a 50% tariff on steel, aluminum and derivative products.

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.

The European Union braced on Friday for a possible letter from U.S. President Donald Trump outlining planned duties on the United States' largest trade and investment partner after a broadening of his tariff war in recent days.

It shows that personal grudges rather than simple economics are a driving force in the U.S. leader’s use of tariffs.