WASHINGTON — One of the two panda cubs born this weekend at the National Zoo has died, according to the zoo’s official Twitter account.

“We are sad to report that the smaller of the two panda cubs has died,” the zoo said in a tweet on Wednesday afternoon.

Giant panda Mei Xiang delivered two offspring hours apart on Saturday night. Zoo officials said at the time that the cubs were “vulnerable” given their size, but both appeared to be healthy.

Mei Xiang has two other children: Tai Shan, born in 2005 and who lives in China, and Bao Bao, who is 2.