South Korea Monday confirmed three new cases of foot-and-mouth disease, bringing the total to 56 since the country's worst outbreak began a month ago.
The agriculture ministry said the new cases were on cattle and pig farms in Yangpyeong county, 55 kilometres (34 miles) east of Seoul, the western port city of Incheon and the southeastern county of Cheongsong.
"About 389,000 animals have been or will soon be culled around the country... numerically, this is the worst outbreak we have ever had," said a ministry official who declined to be named.
The ministry estimates losses related to the disease at around 400 billion won (347.5 million dollars).
About 160,000 animals were slaughtered during the previous worst outbreak in 2002.
In a desperate attempt to curtail the spread of the disease, the government on Saturday launched vaccinations for some 56,000 cattle -- risking a longer export ban from overseas.
It takes longer for a country that launches vaccinations to regain disease-free status from the World Organisation for Animal Health than when the disease is curbed solely by culling.
The battle is facing another obstacle -- a cold snap that froze disinfectant and spraying equipment. "The situation was pretty hard over the weekend, but it's getting better," said the ministry official.
Some events have been cancelled for fear of spreading the outbreak.
The southeastern province of North Gyeongsang, which has lost most livestock during the latest outbreak, decided to scrap most state-organised fairs and festivals.
President Lee Myung-Bak on Sunday urged officials to provide "maximum support" to farmers and health officials fighting the disease, including offering gloves, earmuffs and other cold weather gear.
Previous outbreaks in January and April this year cost more than 250 billion won and left nearly 50,000 animals slaughtered.
Foot-and-mouth disease affects cloven-hoofed animals such as cattle, pigs, deer, goats and sheep.
Explore further: Princeton to start mass meningitis B vaccinations