The United States on Monday launched separate disputes at the World Trade Organization against China, the European Union, Canada, Mexico and Turkey. "The U.S. steel and aluminum duties imposed by President Trump earlier this year are justified under international agreements the United States and its trading partners have approved. However, retaliatory duties on U.S. exports imposed by China, the EU, Canada, Mexico and Turkey are completely without justification under international rules," the U.S. Trade Representative said in a statement.