The central parity of the Renminbi (RMB), or China's currency yuan, weakened to 6.7901 per U.S. dollar on Tuesday from Monday's 6.7890, according to the data released by the China Foreign Exchange Trading System.

On Monday, the central parity of RMB against the U.S. dollar rose to 6.7890, the strongest since China announced to unpeg the yuan from the U.S. dollar in July 2005.

The yuan closed at 6.7967 per U.S. dollar on over-the-counter market in Shanghai Monday.

China's central bank announced on June 19 that it would further the reform of the formation mechanism of the yuan exchange rate to improve its flexibility.