WASHINGTON, March 8 (Reuters) - U.S. President Donald Trump's import tariffs on steel and aluminum will start in 15 days with initial exemptions for Canada and Mexico and the possibility of alternatives for other nations, a senior administration official said on Thursday.
Trump's proclamations on Thursday ordering the tariffs of 25 percent on steel and 10 percent on aluminum will allow other countries to discuss with the administration "alternative ways" to address the national security threat caused by their steel and aluminum exports to the United States, the official said.
Asked whether those ways would include voluntary export restraints, the official did not provide specifics, saying only that the order could be "flexibly modified."
The exemptions for Canada and Mexico would start immediately, but their continuation would depend partly on progress in negotiations to modernize the North American Free Trade Agreement, the official said. He added that NAFTA was an important part of the U.S.-Canada-Mexico security relationship. (Reporting by David Lawder Editing by Paul Simao)