Twenty-three tigers have died at a zoo in Thailand after they ate raw chicken infected with bird flu.
The zoo has been closed to visitors
The Sriracha Tiger Zoo in central Chonburi province was shut to the public on Tuesday pending a full investigation.
Up to 30 more tigers are reported to be ill at the zoo, which is home to more than 200 Bengal tigers.
"All 23 dead tigers had bird flu," said Charal Trinvuthipong, of the Bird Flu Prevention and Elimination Center.
"We believe that the tigers contracted bird flu because they
ate chicken carcasses, and we believe the carcasses had
bird flu," he said.
A recent outbreak of bird flu has ravaged Asian poultry and left more than 30 people dead.
It has also affected domestic cats in Thailand, although health officials have played down the risk of the animals passing the disease to humans.
There has so far been only one possible case of the virus passing from human to human, but officials said it was a one-off.
Health experts are worried that if the virus mixes with a regular human influenza strain, it might create a mutant form that was able to pass between humans, triggering a human flu pandemic.