(The Hill) — President Trump on Saturday announced his administration would levy a 30 percent tariff on goods from Mexico and members of the European Union beginning Aug. 1, targeting two of the U.S.’s top trading partners.

Trump posted separate letters on Truth Social to Mexican President Claudia Sheinbaum Pardo and European Commission President Ursula von der Leyen informing them of the tariff rates.

In his letter to Sheinbaum Pardo, Trump cited the flow of fentanyl across the southern border, which was the original basis for a 25 percent tariff he imposed on Mexican goods earlier this year.

“Mexico has been helping me secure the border, BUT, what Mexico has done, is not enough,” the president wrote.

The U.S. had previously imposed a 25 percent tariff on Mexican goods, though Trump later exempted products covered under the 2020 trade agreement struck between the U.S., Canada and Mexico. It’s unclear whether those exemptions will still apply as of Aug. 1.

The letter to von der Leyen was focused on trade concerns. Trump has in the past claimed the European Union has long been unfair to the U.S. and claimed that the bloc of nations was created to “screw” America.

“We have had years to discuss our Trading Relationship with The European Union, and have concluded that we must move away from these long-term, large, and persistent, Trade Deficits, engendered by your Tariff, and Non-Tariff, Policies and Trade Barriers,” the president wrote.

U.S. Census Bureau data shows that Mexico has been the top trading partner with the U.S. so far this year. EU members like Germany, Italy, France and the Netherlands were also among the top 15.

Trump this week has posted letters to social media sent to more than a dozen countries vowing to impose steep tariffs on their imports starting Aug. 1. Those tariffs are set to go into effect after an initial round of duties unveiled in April were paused for 90 days to allow time for negotiations.

But the U.S. has only brokered a trade agreement with the United Kingdom in that time and announced the framework of deals with China and Vietnam.