Washington's National Zoo says one of its two newborn panda cubs has died after three and a half days.
The zoo's adult female panda Mei Xiang gave birth to the first cub Saturday at 5:35 pm and a second cub about five hours later.
If both cubs had survived, they would have been the 17-year-old panda's third and fourth surviving offspring.
The zoo says the remaining cub appears to be strong and behaving normally.
This is not the first time that Mei Xiang has lost a cub. A stillborn cub was born in 2013. And in 2012, Mei Xiang gave birth to a cub that died after just six days.
Mei Xiang has two other surviving cubs, born in 2005 and 2013.