BEIJING, April 10 -- China's central bank signed a currency swap agreement valued at 30 billion yuan (4.9 billion U.S. dollars) with the South African central bank on Friday.

The agreement lasts for three years, and can be extended upon agreement by both sides, said a spokesman for the People's Bank of China (PBOC).

The deal aims to facilitate bilateral trade and investment as well as maintain regional financial stability.

The PBOC also signed swap agreements with Armenia and the Republic of Suriname in March. To promote international use of the yuan, China has signed currency swap agreements with more than 20 countries and regions since the onset of the global financial crisis in late 2008.