WASHINGTON - Giant pandas Mei Xiang, Tian Tian and their male cub Xiao Qi Ji departed the Smithsonian's National Zoo in Washington, D.C. on Wednesday, wrapping up their stay in the United States and embarking on a journey back to China.

At a brief ceremony held at the zoo, keepers escorted three special crates each holding one panda to travel on Olmsted Walk in front of members of the press. The crates were later loaded on trucks heading to the Dulles International Airport.

Prior to the emergence of the panda crates, the zoo staff loaded supplies including 100 kg of bamboo on the trucks for the pandas to consume during their flight to China.

In remarks addressing the media, Brandie Smith, director of the Smithsonian's National Zoo and Conservation Biology Institute (NZCBI), hailed the China-U.S. collaboration on giant panda conservation that dated back over 50 years, which facilitated Mei Xiang and Tian Tian arriving in Washington, D.C. in 2000 and producing four adorable cubs in the years that followed.

"They are an iconic animal for the zoo, for the District of Columbia, and for our country as well," Smith said of the panda couple and their offspring. "There are billions of people who have admired, celebrated, loved our giant pandas, and have participated in their conservation," she said, adding the zoo was honored and grateful to their Chinese counterparts for making joint efforts in panda research and breeding.