A giant panda has given birth to twins at the Smithsonian National Zoo in Washington.
The cubs, the only giant pandas born in the US this year, are both believed to be healthy and are communicating well.
The pregnancy was the result of artificial insemination in April with frozen semen from Hui Hui, a Chinese giant panda.
Hui Hui lives at the China Conservation and Research Center for the Giant Panda in Sichuan province where the mother panda, Mei Xiang is originally from.
We can confirm a second cub was born at 10:07. It appears healthy. #PandaStory pic.twitter.com/MH0kmQ32kk
— National Zoo (@NationalZoo) August 23, 2015
Mei Xiang was also inseminated with semen from Tian Tian, Washington Zoo's male giant panda. A paternity will be done to find out which of the two is the father.
The sex of the new cubs will be determined using DNA as soon as zoologists are able to do so.
Mei Xiang and Tian Tian already have two cubs together – Tai Shan born in 2005 and Bao Bao born in 2013.
Tai Shan was returned to China in 2010 and Bao Bao remains with her mother.
The National Zoo shared the live footage of Mei Xiang's labour and the twin's birth on their website. The two cubs were born about five hours apart.
At birth, baby pandas are on average 900 times smaller than their mothers.
Bao Bao, who turned 2-years-old on 23 August, has become the zoo's biggest star. Every moment of her life has been captured on the zoo's live cameras from her first steps to her first birthday cake.
In January they shared footage of Bao Bao playing in the snow for the first time.
The director of the National Zoo, Dennis Kelly, said in a press conference: "All of us are thrilled that Mei Xiang has given birth. We know Mei is an excellent mother."
"It doesn’t get old for us. We’re very excited to share this with you guys, our new cub," panda biologist Laurie Thompson said before the second twin was born.
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Mei Xiang, a 17-year-old female weighing over 16 and a half stone, has had five previous "pseudo-pregnancies" where she showed false signs of carrying cubs.
If they continue to progress well, the giant panda will spend the next few weeks bonding in her den with her cubs unaided by zoo staff, officials said.
