President Donald Trump listens during a meeting with steel and aluminum executives last week. Photograph: Evan Vucci/AP

Roberto Azevedo used remarks in Geneva to appeal for calm, saying member states must stop "the fall of the first dominoes" - hours after the European Union said it was preparing a "decisive" response to plans that, US President Donald Trump hopes, will boost US competitiveness. Trump prompted fury among major trading partners worldwide last week when he announced proposals for 25% tariffs on steel products and 10% on aluminium.

His administration has since made it clear the tariffs - due to be announced formally this week - would apply to imports from any country, including the UK.