China's newest panda cubs have been treated to a traditional celebration to mark their one-month birthday.

A large crowd turned out for their first look at Zhenzhen and Qiaoqiao, the fourth set of twin panda cubs to be born to their 12-year-old mother, Qi Zhen. Children with special outfits and panda masks joined in Sunday's festivities to honor the frolicking cubs.

The cubs were born at the Chengdu Giant Panda Research and Breeding Base in southwestern China, which began 24 years ago with six aged and ailing giant pandas. The center's panda population now stands at about 100.

Base director Zhang Zhihe told Chinese television the birth of the pandas represents a new life for his center as well as for the cubs.

He said he hopes affection for the pandas will encourage people to take better care of the environment, for their own sake, as well as that of the animals.