WASHINGTON (AP) - President Donald Trump has signed proclamations imposing tariffs on imports of steel and aluminum.

  

Trump says a 25 percent tariff will be added to steel and a 10 percent tariff will apply to aluminum.

  

The president was surrounded by steel and aluminum workers as he explained his decision at a White House ceremony. He signed separate proclamations ordering the tariffs.

  

Trump says the levies will take effect in about 15 days. He says Canada and Mexico could be exempted based on the outcome of talks to renegotiate the North American Free Trade Agreement.

  

Trump invited the workers to speak. Several spoke of how excessive "dumping" of steel and aluminum imports had negatively affected their jobs and families.