European steelmakers are among the biggest losers from the U.S. and European Union's tariff deal, adding to the problems of an industry already under pressure from multiple directions. Steel and aluminum tariffs are set to stay at 50%.

"I think it's the biggest deal ever made," Trump said of the new agreement, which will reduce the bloc's tariff rate to 15 percent.

Both sides hailed the agreement as the biggest ever. But it will come at a cost to the European Union, and many details have yet to be nailed down.