US President Donald Trump announced a sharp increase in tariffs on imported steel and aluminum, raising them from 25 percent to 50 percent. Speaking at a rally near Pittsburgh, Trump said the move aims to strengthen the US steel industry and protect American jobs, according to Reuters.

The new tariffs, which go into effect Wednesday, will apply to both raw metals and related products. The statement coincided with Trump's approval of a $14.9bn merger between Nippon Steel and US Steel.

Allies criticized the decision, with Canada and Australia describing it as damaging to economic cooperation and commerce. Meanwhile, Cleveland-Cliffs Inc's shares rose 26 percent on anticipation of increased profitability as tariffs rise, Reuters reported.