A zoo keeper attends one of the twin cubs born by five-year-old giant panda Yaya at the Chongqing Municipality Zoon in southwest China , Wednesday, September 6, 2006. The twins brought the number of newborn cubs this year to 15. [Xinhua]

CHONGQING -- A five-year-old panda gave birth to two cubs in southwest China's Chongqing Municipality, bringing the number of cubs born this year to 15.

An air-conditioner was installed in the room to protect the mother, Yaya, from the region's on-going heat wave.

One of the twins were sent to the panda research center in Sichuan, as experts say Yaya does not have enough mother's milk to support two cubs.

Yaya was mated with eleven-year-old Ling Ling in April after being shown on panda mating.

The giant panda, found only in China, is one of the world's most endangered species.

Last year 25 panda cubs were born in captivity. Twenty-one survived.

Experts had previously estimated that there were 1,590 giant pandas living in the wild in China, but Chinese and British scientists announced in June that there could be as many as 3,000 after a survey used a new method to profile DNA from giant panda feces.

The State Forestry Administration said there are more than 180 giant pandas living in captivity on the Chinese mainland.