Russia has reported an outbreak of highly pathogenic H5N2 bird flu on a farm in the Kostromskaya Oblast region, the Paris-based World Organisation for Animal Health (OIE) said on Friday.

The disease was detected on Dec. 17 and led to the culling of more than 660,000 birds, the OIE said, citing a report from the Russian ministry of agriculture.

It did not specify the type of birds that were infected.