The U.S. Congress is the source of pressure for a revaluation in the yuan but China will only reform its foreign exchange regime gradually, its central bank governor said on Sunday. Zhou Xiaochuan, governor of the People's Bank of China, told reporters: "Chinese people do not discuss too much the exchange rate. The pressure is coming from the U.S. Congress but we don't mind." "We have adopted gradual reforms to do our preparation (for macroeconomic reforms)," he said on the sidelines of the annual meeting of the Bank for International Settlements, Reuters reported. The United States is pushing China to revalue its yuan, pegged at 8.28 to the dollar, saying the currency is undervalued and gives China an unfair trade advantage. Washington issued an ultimatum to China in May, saying that if Beijing failed to let the yuan appreciate by October it faced the possibility of being named a currency manipulator, which in turn could invite trade sanctions. --More 2322 Local Time 2022 GMT