WASHINGTON (Reuters) - All countries affected by proposed U.S. tariffs on steel and aluminum have been invited to negotiate exclusions from the measures, which will take effect within 15 days after U.S. President Donald Trump signs proclamations on Thursday, the Associated Press reported.

Quoting people briefed on the plans, AP said countries will be granted exemptions from the tariffs if they can address the threat their exports pose to the United States.

Trump will sign proclamations ordering import tariffs of 25 percent on steel and 10 percent on aluminum at a White House ceremony later on Thursday.