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 plans to retaliate against the United States for new steel and aluminum tariffs, adding another element to rising global trade tensions. "Unjustified tariffs on the EU will not go unanswered—they will trigger firm and proportionate countermeasures,

The European Commission said on Monday it would react to protect EU interests after U.S. President Donald Trump's announcement of impending metals tariffs, but will not respond until it has clarification of the measures.