President Donald Trump threatened to respond to any European “digital services tax” on U.S. companies by imposing a 100% tariff on imports from the countries that implement it.

In a social media post, Trump said “numerous European countries” were discussing the “imminent” implementation of a tax targeting American technology firms. He wrote that any country that imposes such a tax would be “immediately met with a 100% TARIFF on any and all Goods sent” to the United States, and that the new penalty would override any trade arrangements previously negotiated with the U.S.

The threat arrives as the U.S. and the European Union work toward a tariff deal that caps most EU exports at 15%. Digital taxes were not part of that agreement and remain a sticking point between Washington and Brussels.

Trump has previously taken a tough stance against foreign efforts to tax or regulate U.S. tech giants, using tariffs as leverage to deter digital-services levies.