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.

BRIDGEWATER, New Jersey (AP) — President Donald Trump on Saturday announced he’s levying tariffs of 30% against the European Union and Mexico. Trump announced the tariffs on two of the United States’ biggest trade partners in letters posted to his social media account.

Leaders from both economies had been trying to negotiate more favorable terms, only to have those efforts blown up by form letters.