The People's Bank of China (PBOC) on Thursday drained 236 billion yuan ($33.3 billion) from the interbank market through central bank bill issues and repurchase transactions.

The PBOC issued to primary traders 50 billion yuan of three-year bills and 80 billion yuan of three-month bills with yields of 4.56 percent and 3.40 percent, respectively. Both yields were flat from last week.

The central bank also conducted 100 billion yuan of 28-day repos at a yield of 3.20 percent and 6 billion yuan of 91-day repos at a yield of 3.38 percent.

Analysts said the PBOC was using more open market operations to absorb excess liquidity as the interest rate cuts in the United States had left it with a more difficult choice to raise the rates.

The large size of open market operations was sending the market clear signals of further efforts to curb the inflation that surged to an almost 12-year high of 8.7 percent in February.