South Korea's agricultural ministry said Thursday it is investigating two suspected cases of highly pathogenic bird flu from farms amid looming concerns over a nationwide spread of the virus due to migratory birds.

After reporting this year's first farm-related bird flu case in late November, the country has so far reported 16 cases of highly pathogenic influenza, according to the Ministry of Agriculture, Food and Rural Affairs.

With the country culling poultry within a 3-kilometer radius of infected farms, authorities have completed destroying 5.5 million birds, including 3.5 million chickens.

South Jeolla Province accounts for the highest number of confirmed cases at six. There are also infections being reported across the country, including Gyeonggi Province that surrounds the capital city.

Highly pathogenic avian influenza is contagious, and can cause severe illness and even death in poultry.

The country reported this year's first highly pathogenic avian influenza case from wild birds in late October. Since then, a total of 29 cases have been found from wild bird habitats nationwide.

Authorities are currently investigating 14 suspected cases from wild birds. (Yonhap)