China's central bank on Tuesday pledged to keep the exchange rate of the Chinese yuan "basically stable at a reasonable and balanced level."

There is no one-to-one correspondence between the bilateral exchange rate of the yuan against the U.S. dollar and the U.S. dollar index, said the People's Bank of China (PBOC) in a statement on its official WeChat account.

Under the market-oriented exchange rate formation mechanism, the exchange rate is unpredictable, said the PBOC, adding that two-way fluctuations are normal and there will be no "unilateral market."

Additionally, the central bank pledged two days ago to make its currency more convenient for cross-border investment and financing.

The PBOC will "steadily advance the internationalization of the Chinese yuan," it said in a statement on its official WeChat account on Sunday.