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,

French steelmaker Aperam on Tuesday called on Brussels to intervene to curb imports if new 25% tariffs on all steel and aluminium imports into the United States prompt companies to ship more to the European Union instead.

The 25 percent tariffs on imported steel and aluminum are the latest salvo in his ongoing effort to overhaul the U.S. trading relationship with the rest of the world.