The US Federal Reserve is monitoring currency markets “closely” and will conduct policy in a way that will “help ensure that the dollar is strong”, Ben Bernanke said on Monday. In rare comments apparently aimed at reassuring markets and foreign governments, the Fed chairman said the central bank was “attentive” to the implications of changes in dollar’s value and mindful of the impact of rising commodity prices when evaluating the outlook for inflation. The dollar briefly jumped on his remarks, but gave up some gains as traders questioned how far Bernanke was prepared to go to support the currency.