CHENGDU -- Germany-born giant panda twins arrived safely in the southwestern Chinese city of Chengdu on Sunday morning, according to the Chengdu Research Base of Giant Panda Breeding.

The twins, named Meng Xiang and Meng Yuan in Chinese, were transported by Air China's Boeing 777F cargo plane. The flight took just over 10 hours.

In June 2017, the twins' parents -- the female Meng Meng and male Jiao Qing -- arrived at Zoo Berlin in Germany from Chengdu, starting a 15-year residency.

The zoo built them a panda park covering nearly 5,500 square meters. On Aug. 31, 2019, Meng Meng gave birth to the twin cubs.

Generally, giant panda cubs born overseas return to China between two and four years old to avoid inbreeding during the reproductive period of four to six years old.

In line with the agreement between Zoo Berlin and the China Wildlife Conservation Association, the twins returned to their hometown of Chengdu after living in Berlin for four years.