Trump announced the tariffs on two of the United States’ biggest trade partners in letters posted to his social media account.

In his letter to Mexico’s leader, Trump acknowledged that the country has been helpful in stemming the flow of undocumented migrants and fentanyl into the United States. But he said the country has not done enough to stop North America from turning into a “Narco-Trafficking Playground.”

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

Trump in his letter to the European Union said that the U.S. trade deficit was a national security threat.

“We have had years to discuss our Trading Relationship with The European Union, and we have concluded we must move away from these long-term, large, and persistent, Trade Deficits, engendered by your Tariff, and Non-Tariff, Policies, and Trade Barriers,” Trump wrote in the letter to the EU. “Our relationship has been, unfortunately, far from Reciprocal.”

Trump is in the midst of an announcement blitz of new tariffs with allies and foes alike, a bedrock of his 2024 campaign that he said would set the foundation for reviving a U.S. economy that he claims has been ripped off by other nations for decades.

With the reciprocal tariffs, Trump is effectively blowing up the rules governing world trade. For decades, the United States and most other countries abided by tariff rates set through a series of complex negotiations known as the Uruguay round. Countries could set their own tariffs – but under the “most favored nation’’ approach, they couldn’t charge one country more than they charged another.

With Saturday’s letters, Trump has now issued tariff conditions on 24 countries and the 27-member European Union.

The European Union’s chief trade negotiator said earlier this week that a trade deal to avert higher tariffs on European goods imported to the U.S. could be reached “even in the coming days.” Maroš Šefčovič told EU lawmakers in Strasbourg, France on Wednesday that the EU had been spared the increased tariffs contained in the letters Trump sent on Monday, and that an extension of talks would provide “additional space to reach a satisfactory conclusion.”

The bloc collectively sells more to the U.S. than any other country. U.S. goods imports from the EU topped $553 billion in 2022, according to the Office of the U.S. Trade Representative.

Trump on April 2 proposed a 20% tariff for EU goods and then threatened to raise that to 50% after negotiations did not move as fast as he would have liked. Sefcovic did not mention any tariff figures.

The higher tariffs as well as any EU retaliation had been suspended as the two sides negotiate. However the base rate of 10% for most trade partners as well as higher rates of 25% on autos and 50% on steel and aluminum had gone into effect.

Douglas Holtz-Eakin, a former Congressional Budget Office director and president of the center-right American Action Forum, said the letters were evidence that serious trade talks were not taking place over the past three months. He stressed that nations were instead talking amongst themselves about how to minimize their own exposure to the U.S. economy and Trump.

“They’re spending time talking to each other about what the future is going to look like, and we’re left out,” Holtz-Eakin said.

He added that Trump was using the letters to demand attention, but, “In the end, these are letters to other countries about taxes he’s going to levy on his citizens.”