The United States has launched five separate World Trade Organisation dispute actions challenging retaliatory tariffs imposed by China, the European Union, Canada, Mexico and Turkey following US duties on steel and aluminium.
The retaliatory tariffs on up to a combined $US28.5 billion ($A38.3 billion) worth of US exports are illegal under WTO rules, US Trade Representative Robert Lighthizer said in a statement on Monday.
"These tariffs appear to breach each WTO member's commitments under the WTO Agreement," he said. "The United States will take all necessary actions to protect our interests, and we urge our trading partners to work constructively with us on the problems created by massive and persistent excess capacity in the steel and aluminium sectors."
Lighthizer's office has maintained that the tariffs the US has imposed on imports of steel and aluminium are acceptable under WTO rules because they were imposed on the grounds of a national security exception.
Mexico said it would defend its retaliatory measures, saying the imposition of US tariffs was "unjustified".
"The purchases the United States makes of steel and aluminium from Mexico do not represent a threat to the national security," Mexico's Economy Ministry said in a statement.
"On the contrary, the solid trade relationship between Mexico and the US has created an integrated regional market where steel and aluminium products contribute to the competitiveness of the region in various strategic sectors, such as automotive, aerospace, electrical and electronic," the ministry added.
Lighthizer said last month that retaliation had no legal basis because the EU and other trading partners were making false assertions that the US steel and aluminium tariffs are illegal "safeguard" actions intended to protect US producers.
Australian Associated Press
