China's central bank unexpectedly cut key policy rates for the second time in three months on Tuesday, in a fresh sign that the authorities are ramping up monetary easing efforts to boost a sputtering economic recovery.

Industrial and Commercial Bank of China Ltd (601398.SS), Agricultural Bank of China Ltd (601288.SS), Bank of China Ltd (601988.SS) and China Construction Bank Corp (601939.SS) all cut their rates from Thursday, websites from each bank showed.