Global currency wars pose “a real threat” to economic recovery, the head of the International Monetary Fund, Dominique Strauss-Kahn, has warned.
In an interview with the BBC, he said currency disputes showed countries were not co-operating as well as they had during the financial crisis.
In recent weeks both the US and Europe have led criticism of China over its undervalued yuan.
Meanwhile, Japan been forced to intervene to curb rises in the yen.
Mr Strauss-Kahn said there were signs that countries were trying to use their currencies “as a weapon”.
