BEIJING- China's central bank drained 70 billion yuan ($11 billion) from the financial system through open market operations Thursday, with the volume of maturing securities exceeding new injections.

The People's Bank of China (PBOC) pumped 40 billion yuan into the market through reverse repos, with 110 billion yuan of contracts maturing, leading to a net withdrawal of 70 billion yuan.

The PBOC said the move was to maintain liquidity "at a reasonable and stable level," noting that a relatively high liquidity level in the banking system and local treasury cash management could offset the impact of maturing securities to some extent.

A reverse repo is a process by which the central bank bids and buys securities from commercial banks, with an agreement to sell them back in the future.

On Thursday, the PBOC conducted 20 billion yuan of seven-day reverse repos at an interest rate of 2.55 percent, and 20 billion yuan of 28-day reverse repos at 2.85 percent. Both rates were unchanged from the previous operations.

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