President Donald Trump signed an order Monday imposing global tariffs of 25% on all steel and aluminum imports, likely pleasing domestic steelmakers but hurting allies like Canada and Mexico.

The European Union said it would respond with "firm and proportionate countermeasures" after U.S. President Donald Trump's decision to impose tariffs on all steel and aluminium imports, escalating fears of a trade war.

The president imposed a 25 percent tariff on global metals, repeating a move from his first term. Economists and foreign governments know what will come next.