Two female giant pandas born in the United States returned to their hometown Sunday in southwest China's Sichuan Province.

The panda sisters, Su Lin and Zhen Zhen, left San Diego, California on Saturday. After a stopover in Shanghai, they arrived at the Chengdu Shuangliu International Airport at 3:00 PM, the Wolong Giant Panda Protection and Research Center said.

They will arrive at the center's Bifengxia base in Ya'an later Sunday accompanied by the center's veterinarians and keepers, the center said.

Isolated shelters and keepers have been assigned to them, said Li Desheng, panda expert with the Wolong center.

The sisters will be in quarantine for one month during which they will get used to the climate, environment, food and keepers before going in front of the public.

Su Lin and Zhen Zhen were born in 2005 and 2007 respectively in the Zoo of San Diego. Their father, "Gao Gao," and mother, "Bai Yun," were sent to the United States on panda breeding research programs aimed at increasing global understanding of the endangered species' feeding and breeding patterns.

Thirteen pandas have been born overseas under the programs with nine surviving. According to the program agreement, all pandas born overseas belong to China.

A total of six pandas have been returned to China since 2004 when the first American-born panda Hua Mei came back home.

Giant pandas are the world's most endangered species. About 1,600 live in the wild in Sichuan and its neighboring Gansu and Shaanxi provinces, while over 300 are kept in captivity.

(Xinhua News Agency September 27, 2010)