The US economy is in “uncharted waters,” Federal Reserve vice-chairman Don Kohn said on Tuesday, warning that both financial and economic recovery was likely to be slow.

Mr Kohn said inflation was also an “area of concern”. But he characterised recent inflation news as “mixed” rather than bad. His comments came as new data showed that input price inflation was lower than expected in April, but core input prices – excluding food and energy – rose at twice the expected rate.