The farm in Nonsan, 132 miles south of Seoul, was put under quarantine after birds began dying and a drop in egg output was noticed, the Agriculture Ministry said, Yonhap news agency reported.

The government said the suspected case is the first such this year in that region. Other outbreaks this year have been mostly confined to the southwestern Jeolla region.

The Nonsan case brings the total reported bird flu cases this year to 50. Of that total, the government said, 26 cases were confirmed as avian influenza, eight proved negative, while the remaining 16 were being tested.

So far, 5.33 million birds have been culled and buried since the first outbreak was reported in early April, the report said.