IMF managing director Rodrigo Rato said European Central Bank interest rates are appropriate at present, although the ECB should not rule out a rate cut if growth remains weak. "If the weakness of domestic demand persists beyond the first half or third quarter, then it will be necessary to act and monetary policy is one of those actions," he said. But the present euro zone growth slowdown is likely to be short-lived, he said. There are no major inflation risks for the euro zone at the moment, he said. Rato also said that euro zone monetary union has been a success and it would not be advisable for countries to consider leaving the euro, although more structural reforms are needed in the euro zone. "The euro is one of Europe's big successes, a very important instrument to help European countries in a globalised world," Rato said. He said global current account imbalances represent a growing risk for the world economy. US budget policy is moving in the right direction, but not fast enough, he said. And he said China needs to move towards a flexible exchange rate system for the yuan. Rato said a move to more flexible exchange rates in China and other Asian economies would be in the interest of those countries, although it would not have a major immediate impact on growth and savings rates.