BEIJING - China's central bank on Monday injected funds into the banking system via open market operations to ease a liquidity strain.

The People's Bank of China conducted 100 billion yuan ($15.9 billion) of seven-day reverse repos, 30 billion yuan of 28-day reverse repos and 20 billion yuan of 63-day reverse repos, pumping a total of 150 billion yuan into the market.

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

The central bank said the move aims to offset factors such as the commercial banks' payment of required reserves, and maintaining liquidity in the banking system at a reasonable and stable level.

The interest rates for seven-day, 28-day and 63-day operations were unchanged at 2.5 percent, 2.8 percent and 2.95 percent respectively.

In Monday's interbank market, the overnight Shanghai Interbank Offered Rate, which measures the cost at which banks lend to one another, rose slightly to 2.57 percent despite the liquidity injection, but the rate for one-month loans dipped to 4.04 percent.