The attack comes days after the Organisation for Economic Co-operation and Development delivered an unprecedented rebuke to the US that its protectionist measures on farming and steel could poison the new round of trade talks. The OECD, made up of 30 wealthy nations including the UK, was joined by the International Monetary Fund, the World Bank and the World Trade Organisation in voicing concerns that Washington's actions could set off a chain reaction of worldwide protectionism that would particularly hurt developing countries.