BEIJING, July 13 (Xinhua) -- China's central bank Friday injected 188.5 billion yuan (about 28.3 billion U.S. dollars) into the market via the medium-term lending facility (MLF) to maintain liquidity.

The People's Bank of China said the injected funds would mature in one year at an interest rate of 3.3 percent.

On Friday, 188.5 billion yuan of MLF contracts and 20 billion yuan of reverse repo securities matured, resulting in a net withdrawal of 20 billion yuan from the market.

The MLF tool was introduced in 2014 to help commercial and policy banks maintain liquidity by allowing them to borrow from the central bank using securities as collateral.

The central bank increasingly relies on open-market operations, rather than changes in interest rates or reserve requirement ratios, to manage liquidity in a more flexible and targeted manner.

China will maintain a prudent and neutral monetary policy in 2018 as it strives to balance growth and risk prevention.