Shares in Asian manufacturers tumbled on concern that tariffs will hurt trade in North America and disrupt global supply chains.

Trump has long proposed raising tariffs—or taxes on imported goods that the businesses importing them pay the U.S. government—before the election, and said in November he’ll impose a 25% tariff rate on all imports from Mexico and Canada on the first day of his presidency and will impose an additional 10% tariff rate on all imports from China on top of other tariffs.

President Donald Trump signed an order to put tariffs on U.S. neighbors Canada and Mexico, as well as China, starting Tuesday.