The EU – the United States' biggest trading partner – had been scheduled to impose "countermeasures" starting Monday at midnight in Brussels

Aircraft, machinery, cars, chemicals and medical devices are the leading big-ticket items on the latest list of U.S. goods the European Commission has proposed to impose tariffs on if talks with Washington do not yield an agreement on trade.

President Trump is threatening Mexico and the European Union, two of the largest U.S. trading partners, with 30% tariffs starting in August if they don't reach a trade deal with the U.S. CBS News MoneyWatch correspondent Kelly O'Grady breaks down what this means for U.

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.

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

It comes as US President Donald Trump threatens to impose 30% tariffs on imports from the European Union and Mexico.

Tariff revenues have brought in more that $113 billion so far this year, according to the Treasury Department data. The U.S. received more than $27 billion in customs duties in June alone.

"Imposing 30 percent tariffs on EU exports would disrupt essential transatlantic supply chains, to the detriment of businesses, consumers and patients on both sides of the Atlantic," European Commission President Ursula von der Leyen said in a statement on July 11, in a response to Trump's letter.