Two female giant pandas born in the U.S. will return to their hometown in southwest China this month, the Wolong Giant Panda Protection and Research Center said Saturday.

The sister pandas, Su Lin and Zhen Zhen, will leave San Diego, California for southwest China's Sichuan Province on Aug. 23, stopping on the way at Shanghai.

The pandas will be in a rigorous quarantine for one-month at the Ya'an breeding base before they are shown to the public.

Su Lin and Zhen Zhen were born in 2005 and 2007, respectively. Their father, "Gao Gao", and mother, "Bai Yun", were sent to the United States for panda breeding research programs. The program seeks to increase global understanding of the endangered species' feeding and breeding patterns.

According to the program agreement, all pandas born overseas belong to China.

About 1,600 giant pandas live in the wilds in China, mostly in Sichuan Province and the northwestern provinces of Shaanxi and Gansu. Another 290 are in captive-bred programs worldwide, mainly in China.