European Union ambassadors reached broad agreement on Sunday to intensify efforts to dissuade U.S. President Donald Trump from imposing tariffs on European allies, while also preparing retaliatory measures should the duties go ahead, EU diplomats said. Trump vowed on Saturday to implement a wave of increasing tariffs from February 1 on EU members Denmark, Sweden, France, Germany, the Netherlands and Finland, along with Britain and Norway, until the U.S. is allowed to buy Greenland, a step major EU states decried as blackmail.