HONG KONG, China (CNN) -- Authorities in Hong Kong ordered about 80,000 chickens killed Tuesday after discovering dozens of birds had died of bird flu at a farm in the territory.
The order requires all chickens within a 3 kilometer (2-mile) radius of the farm where the dead chickens were discovered Monday to be culled, said Dr. York Chow, Hong Kong's food and health secretary.
"We have discovered up to 60 dead chickens in that farm. After a series of tests, we have confirmed this morning that the chickens did die from the H5 virus," Chow told reporters.
One other farm is affected by the order, he said.
Health officials worldwide have long feared a major human outbreak of the H5N1 flu virus, which has infected numerous bird species in Asia, Europe and Africa. The disease has been passed from poultry to humans in some cases, resulting in more than 200 deaths since 2003.
Human-to-human transmission of avian flu is rare, but officials worry it could mutate and become a deadly pandemic.