North Korea has experienced an outbreak of bird flu since last month, culling tens of thousands of poultry so far, its news agency said Wednesday.

A chicken farm in the capital city of Pyongyang first reported symptoms of avian influenza (AI), known as the H5N1 virus, on March 21, and the virus has been spreading to other poultry farms, the North's Korean Central News Agency (KCNA) reported, citing Director Ri Kyung-kun of its agricultural ministry.

"(We) are suffering from extensive economic damage as tens of thousands (of poultry) have either fallen dead or been culled," the KCNA said.

As part of efforts to contain the highly contagious virus, the North Korean authorities "set up an emergency quarantine commission and declared an emergency prevention situation across the nation," the report added.

"(The government) has controlled traffic, come up with quarantine measures and buried the culled. But the disease shows no sign of dying down and continues to spread," the KCNA said.

North Korea sustained extensive damage by AI last year.

Earlier this year, South Korea also experienced the outbreak of the highly contagious virus, the first since 2011. More than 10 million poultry have been destroyed to prevent the disease from spreading, with the government testing samples from pig and dog farms to confirm it's spread to different species.

The KCNA also confirmed an outbreak of food-and-mouth disease (FMD) in cows, which was first spotted in Kangwon Province near the border on March 14, without elaborating on other details.

In February, the impoverished country said the FMD outbreak at a pig farm in a suburb of Pyongyang the previous month led it to cull thousands of pigs. (Yonhap)