Berlin, February 27 - There are strict limits to what the European Central Bank can achieve with its monetary policy, and national governments must also play their part, European Central Bank president Mario Draghi said Wednesday. "The mandate of the ECB has defined limits. We cannot repair unsound budgets. We cannot clean up troubled banks. We cannot solve deep-rooted problems in the structure of Europe's economies," Draghi said during a speech in Munich. Instead, he called on governments to do more to implement structural reforms aimed at boosting their economies toward their full potential. That is a very important step towards "the crucial challenge" of reducing unemployment, he said. Draghi also maintained the ECB has acted "to ensure price stability".