Alan Greenspan, chairman of the US Federal Reserve, yesterday issued a strong warning about the "increasingly less tenable" US current account deficit, triggering fresh falls in the dollar.

Speaking as finance ministers and central bank governors gathered in Berlin for a G20 meeting of representatives of leading economies, Mr Greenspan hinted that he expected the dollar to bear much of the brunt of adjusting a current account deficit in excess of 5 per cent of gross domestic product.