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.

WASHINGTON—President Trump reignited his global trade war Monday, renewing his threat to hit partners with punishing tariffs even as he announced a three-week extension to negotiate deals. Trump signed an executive order extending the date when his so-called reciprocal tariffs would take effect,

The Yale Budget Lab noted that the letters sent Monday would hike the effective tariff rate on U.S. consumers to the highest since 1934.

China warned the Trump administration on Tuesday against reigniting trade tension by restoring tariffs on its goods next month, and threatened to retaliate against nations that strike deals with the United States to cut China out of supply chains.

Trump Sending Tariff Letters. Trump has also said he would begin sending out tariff letters or announcing trade deals on July 7, as his 90-day pause on his reciprocal tariffs near