President Donald Trump has doubled tariffs on steel and aluminium imports from 25% to 50%, aiming to boost the struggling U.S. metals sector. The new rates took effect Wednesday, with the UK the only exemption due to a provisional trade deal. White House adviser Kevin Hassett said the increase followed data showing the previous rate helped but more support was needed.

The move drew swift criticism from allies. Canada, the largest aluminium exporter to the U.S., is in talks for exemption. Mexico’s Economy Minister Marcelo Ebrard called the decision irrational, citing America’s surplus in steel trade with Mexico. The European Union also warned of possible retaliation, saying the tariffs undermine negotiations.

OECD Chief Economist Alvaro Pereira said the tariffs are hurting global trade and investment, with the U.S. likely to suffer most. Despite ongoing legal challenges, the tariffs remain in force during appeals.