The world's richest nations have rallied behind Japan in the latest bid to calm markets over the devastating earthquake and its aftermath. The G7 group, whose members include the United States and the UK, has pledged to join the Bank of Japan in stepping into the currency markets to curb the soaring yen. Recognising the damage that a rising national currency could do to an export-dependent economy, the Bank of England, Germany's Bundesbank and the Bank of France were among the central banks that joined the BoJ on Friday morning in the first co-ordinated intervention by the G7 since the launch of the euro a decade ago. The US Federal Reserve and the European Central Bank are also expected to participate. The BoJ reportedly bought $25bn (15.5bn) of US currency in the wake of the G7 announcement late on Thursday.