The president, who has threatened and delayed other tariffs, said he will announce the new measures Monday. Canada and Mexico are among the U.S.’s top steel suppliers.

U.S. President Donald Trump said on Sunday he will introduce new 25% tariffs on all steel and aluminum imports into the U.S., on top of existing metals duties. He also said he will announce reciprocal tariffs on Tuesday or Wednesday.

Mr. Trump’s decision to impose tariffs on metals is not new. In his first term, the president levied tariffs on foreign steel and aluminum globally, angering allies like Mexico, Canada and the European Union. He ultimately rolled back some of those barriers on Canada and Mexico when they signed a revised trade agreement with the United States.