President Donald Trump says he will also impose "reciprocal tariffs" on any countries who place tariffs on the US.

Reciprocal tariffs on trading partners are also in the mix as officials say “punitive” tariffs on Mexico and Canada were only a small slice of trade agenda.

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.