China and the United States are working toward transferring a pair of giant pandas to San Francisco in 2025.

The China Wildlife Conservation Association and the San Francisco Zoo signed a letter of intent on giant panda conservation cooperation in Beijing on Friday.

The letter states that the parties will make preparations in accordance with regulations and technical standards to transfer the pandas to San Francisco, which also received a pair of giant pandas on loan from China for three months in 1984.

In the 1990s, China and the US started cooperative research on giant panda protection in the wild, including breeding, and disease control and treatment. The countries have jointly bred 17 baby cubs since then.

Lin Jian, spokesman of the Ministry of Foreign Affairs, said at a recent news conference that the giant panda is not only a national treasure, but loved by people around the world, and the giant panda is an envoy and bridge for friendship.

He said China and the US have tackled many technical problems on giant panda conservation and breeding, and have promoted technology exchanges and enhanced protection of endangered animals and plants, which has boosted friendship and communications between the countries.

Li Desheng, deputy director of the China Conservation and Research Center for the Giant Panda, said that international cooperation on giant pandas and loaning them overseas can let people around the world better understand the species.

He said the giant panda is native to China, and the country is willing to share protection and research experiences with the world and see good results from cooperative research.

"We've worked out some problems including panda's estrus, pregnancy and baby cub breeding, but we still have some other difficult illnesses or diseases yet to be tackled," he said.

He said that China has cooperated with 20 countries and regions on giant panda conservation and research since the 1990s, including Spain, Finland, Japan and the United States.

A thorough evaluation of the giant panda's living environment, breeding ability and animal medical services is performed before choosing a country to cooperate with on research, he added.