SEOUL (Reuters) - South Korea has started culling over300,000 chickens and other poultry after confirming an outbreakof highly virulent bird flu at a farm in the southwest -- itsfirst case in 13 months, the country's farm ministry said.

The ministry said late on Thursday the strain of bird fluat the farm in Gimje, about 215 km (135 miles) south of Seoul,was confirmed as the deadly H5N1 strain. Workers have startedslaughtering birds at the farm and six other farms within 500meters radius of the outbreak site.

On Wednesday, the farm, which raises 150,000 birds,reported the death of around 2,400 birds since last Saturday.

The ministry also banned distribution of 3.6 millionanimals within a 10 km radius of the outbreak site and thedestruction of eggs produced, and already distributed, in thearea.

The country has had seven outbreaks of the deadly H5N1strain of bird flu between November 2006 and March 2007 and hasspent 58.2 billion won ($59.17 million) on quarantine measures.

Bird flu has killed 238 people globally since 2003,according to the World Health Organisation.

It largely remains an animal disease, but the big concernis that it could mutate into a disease that easily passes fromone person to another, triggering a deadly global pandemic.

(Reporting by Miyoung Kim; Editing by Valerie Lee)