The government has intensified its watch level against avian influenza(AI) from "alert" to the highest tier of "serious" amid the rapid spread of bird flu in the country.

Agriculture Minister Kim Jae-soo said Friday that AI has been spreading steadily ever since the first case of the highly pathogenic H5N6 strain was detected on November 17th in the North Chungcheong and South Jeolla provinces.

Citing that as many as 16 million chickens and ducks were culled so far in a span of about a month, he said the strain is more contagious than the H5N8 that plagued the nation in 2014.

The Agriculture ministry released countermeasures that include expanding control zones to the nation's major highways, tentatively shutting down livestock facilities if needed and providing antiviral drugs.