The chief of the World Trade Organisation said today that he is concerned by US President Donald Trump's plans to impose tariffs on steel and aluminium, warning a trade war is "in no-one's interests". "The WTO is clearly concerned at the announcement of US plans for tariffs on steel and aluminium. The potential for escalation is real, as we have seen from the initial responses of others", WTO director-general Roberto Azevedo said in a statement. "A trade war is in no-one's interests. The WTO will be watching the situation very closely." Trump triggered a furore yesterday by announcing he would set tariffs of 25 percent on steel and 10 percent on aluminium to protect US producers. He did not specify if the tariffs would target specific countries, but his announcement caused an outcry among US allies such as Canada, the European Union, Mexico and Australia as well as China, the world's biggest steel producer. During his campaign and as president, Trump and his staff have voiced deep hostility towards the WTO, portraying it as a broken organisation that caters to emerging countries like China at American expense. Azevedo has consistently responded with caution, underscoring his willingness to work with US officials to resolve their grievances. His decision today to publicly condemn a policy announcement by a member-state was a rare move, underscoring the gravity of his concern.