South Korea began slaughtering 236,000 poultry and stepped up quarantine measures yesterday to control an outbreak of deadly bird flu in a hub of its poultry industry.

Health officials, backed by police and soldiers, cordoned off a 10-kilometre radius around the outbreak site in the southern city of Iksan, the agriculture ministry said.

"We have increased quarantine activity, maintaining tight restrictions on the movement of people and vehicles there to stop the virus from spreading," spokesman Yoon Yong-do said.

Blood tests on affected birds showed the virus was the highly contagious H5N1 strain, which battered South Korea three years ago, he said.

"Some 236,000 chickens within a 500-metre radius of the affected farm are being culled and buried," Yoon said, adding ducks, pigs and dogs were also slaughtered.

He said Minister of Agriculture and Forestry Park Hong-soo chaired an emergency meeting yesterday and called for comprehensive action to tackle the outbreak in Iksan.

"We are closely monitoring the area as there are about 5 million chickens in a 10-kilometer quarantine zone, which also includes Halim," Yoon said.

Halim, the country's top chicken meat processor, supplies 20 to 25 per cent of domestic needs and also exports cooked chicken to Japan and other countries.

Neighbouring Japan has already suspended South Korean poultry imports and started requiring people arriving from the country to disinfect their shoes.

The virus can affect people but health officials said no one had shown symptoms of having contracted the flu.

"Blood tests on people in the area showed no one has been affected by the virus," Oh Dae-kyu, head of the National Veterinary Research and Quarantine Service, told reporters.

Nine South Koreans were infected by the H5N1 virus while helping slaughter 5.3 million ducks and chickens from December 2003 to March 2004, but they showed no symptoms of the disease as defined by the World Health Organization.

Source: China Daily