GENEVA, July 10 (Xinhua) -- Switzerland has launched a dispute at the the World Trade Organization (WTO) against "unjustified" U.S. steel and aluminium tariffs, the Swiss economy ministry said Tuesday in a statement.

"From Switzerland's point of view, the additional duties, which according to the U.S. have been introduced to protect national security, are unjustified," the official statement said.

Noting that the United States has not responded to a Swiss request for an exemption from the tariffs to date, Swiss Federal Councillor for Economic Affairs Johann N. Schneider-Ammann decided to "initiate WTO dispute settlement proceedings," the statement said.

Switzerland therefore joined other countries, including Canada, Mexico and Norway, that have requested consultations on U.S. tariffs at the WTO.