Financial markets, which have shown increasing insensitivity to tariff threats from the US, will face a test at the Monday open after President Donald Trump declared a 30% rate for the European Union and Mexico effective Aug.

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 threatened a significant tariff hike on the European Union and Mexico, two of the largest U.S. trade partners, on Saturday. NBC News’ Yamiche Alcindor has more.

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 threatened new tariffs on more than 20 countries this week, but his justification for raising import taxes on Brazil stands out.

The president also decided to send out letters as a way to keep the pressure up.

President Donald Trump posted several more letters on social media on Wednesday, setting tariff rates ranging from 20% for products from the Philippines to 30% for products from Algeria, Iraq, Sri Lanka,

European Commission President Ursula von der Leyen said that there needed to be a “genuine rebalancing” in the China-Europe relationship.