BEIJING - China's central bank Friday continued to pump cash into the financial system to ensure stable liquidity, after it raised interest rates for open market operations the previous trading day.

The People's Bank of China (PBOC) conducted 80 billion yuan ($12.11 billion) of seven-day reverse repos priced to yield 2.5 percent, and 70 billion yuan of 28-day contracts to yield 2.8 percent.

The interest rates stayed unchanged with Thursday's open market operations, which was raised by 5 basis points following the interest rate hike by the US Federal Reserve Wednesday.

The operation resulted in a net injection of 150 billion yuan into the market as no reserve repos were due Friday.

This is the fourth straight day that the central bank has conducted a net cash injection into the market. Friday's injection aims to offset the impact on market liquidity from tax payments and the depositing of required reserves at financial institutions, according to the PBOC.

For the whole week, the central bank has injected a net 368 billion yuan into the market, including 288 billion yuan via a one-year medium-term lending facility (MLF).

The PBOC said in a statement Thursday that it would conduct open market operations in a flexible way to meet the seasonal liquidity needs of banks near the year end.

The central bank has also made arrangements for significant cash demands before the Spring Festival, an important Chinese traditional festival which will fall on Feb 16, 2018.

"The liquidity supply in the banking system near the New Year and Spring Festival is guaranteed," the PBOC said.

The central bank has increasingly relied on open market operations for liquidity management, rather than cuts in interest rates or reserve requirement ratios.

China set the tone of its monetary policy in 2017 as prudent and neutral, keeping appropriate liquidity levels but avoiding excessive liquidity injections.