US President Donald Trump ramped up his tariff threats to the European Union while saying he would speak with the leaders of Canada and Mexico, as stock markets sank following a hectic weekend that saw prospects for a trade war turn into reality.

President Donald Trump on Sunday defended his decision to impose broad tariffs on Canada, Mexico and China, acknowledging they may cause “some pain” but claiming it “will all be worth the price,” as the import taxes have been widely condemned by business groups and economists who warn they’ll raise prices for American consumers.

President Donald Trump signed an order to put tariffs on U.S. neighbors Canada and Mexico, as well as China, starting Tuesday.