Copper futures in New York surged after US President Donald Trump said he planned to implement a 50% tariff on imports of the commodity, a move that’s likely to spark massive supply-chain ripples through global metal markets.

U.S. President Donald Trump on Tuesday said he would impose a 50% tariff on imported copper and soon introduce long-threatened levies on semiconductors and pharmaceuticals, broadening his trade war that has rattled markets worldwide.

Copper prices surged and the Dow industrials slipped on Tuesday after President Trump announced a surprisingly large tariff on imports of the metal, and declared that he would hold firm on his latest deadline for trade deals with foreign countries.