Mario Draghi was speaking to reporters in Frankfurt after the bank's governing council held its key interest rates steady at 1%, as expected, leaving euro zone borrowing costs at historical lows following two months of rate cuts in a row. He said the decision to hold rates was unanimous. Mr Draghi welcomed the new fiscal compact agreed at December's EU summit as an "important contribution" to solving the euro zone debt crisis, but said it would be better if final agreement were reached at the end of this month, and not in March. He also he warned that the wording of any new budgetary rules needed to be "unambiguous and effective". Mr Draghi called for the urgent implementation of bold structural reforms in euro zone countries. He also welcomed EU leaders' statement that private sector involvement in the restructuring of Greek debt was "unique and exceptional". The ECB chief said tensions in the financial markets were continuing to affect economic activity in the euro zone, though there were signs that activity had stabilised recently. But he told reporters that the economic outlook was still "subject to high uncertainty". Mr Draghi said the ECB would continue to provide funding to European banks in order to support confidence. The ECB, which cut interest rates in both November and December by a quarter-point, had been widely expected to hold fire this month as it continues to assess how effective the previous moves have been. Earlier, the Bank of England also kept its key interest rate at a record low 0.5% and opted against altering its stimulus plans despite the fragile state of the British economy. Last month - on the same day that EU leaders met in Brussels in what was seen as a make-or-break debt crisis summit - the ECB brought euro zone borrowing costs back down to their previous historical low of 1%, effectively reversing last year's two earlier rate hikes. On top of that, it offered banks in the region an unlimited amount of liquidity by loosening collateral rules, cutting the minimum reserve ratio and launching new three-year loans at super-cheap rates. With all that now feeding through into the system, the ECB would now want to wait and see how those moves pan out, analysts said.