Futures tracking aluminum and steel prices in the US surged after President Donald Trump said he will double tariffs on the metals this week.Contracts linked to the prices that manufacturers pay to get aluminum delivered to the US Midwest jumped 54% to the highest since 2013 on the Comex exchange in New York on Monday — offering an early glimpse of the much higher costs for American factories,

By Eric Onstad, Hyunjoo Jin and Hongmei Li LONDON/SEOUL/SINGAPORE (Reuters) -U.S. prices of steel and aluminium spiked on Monday while shares of foreign steelmakers slumped after U.S. President Donald Trump said he would double tariffs on imports of the two metals to 50%.