BEIJING, March 12 (Xinhua) -- China's central bank Monday continued to inject liquidity into the banking system via open market operations amid efforts to ease a cash strain.

The People's Bank of China conducted 50 billion yuan (7.9 billion U.S. dollars) of seven-day reverse repos and 40 billion yuan of 28-day reverse repos, pumping a total of 90 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 operations aimed to offset factors such as tax payment, and keep liquidity in the banking system at a reasonable and stable level, the central bank said on its website.

The interest rates for the seven-day and 28-day operations were unchanged at 2.5 percent and 2.8 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 2.59 percent despite the liquidity injection. The rate for one-month loans also climbed to 4.37 percent.