Thousands of poultry are being culled after South Korea confirmed that a preliminary test indicated a possible bird flu outbreak for the first time since 2011.
A suspected case of avian influenza was reported Thursday at a poultry farm in Gochang in North Jeolla Province, some 300 kilometers (187.5 miles) southwest of Seoul, the agricultural ministry said.
Local authorities had already began culling all of the more than 20,000 ducks on the farm, it said.
Quarantine measures were also enforced at 24 other farms in four different provinces that were known to have purchased ducks from the Gochang farm.
Further testing from Gochang was under way, but the ministry said it was "highly likely" it would be confirmed as H5N1 avian flu.
The last outbreak in South Korea occurred in 2011, when more than six million poultry were culled at more than 280 farms across the country.