SEOUL, South Korea -- Most livestock markets in South Korea were ordered closed Tuesday to prevent the spread of foot-and-mouth disease, which officials feared could become a national epidemic.

So far, hundreds of cattle and pigs believed to have been infected have been slaughtered.Foot-and-mouth is highly communicable and can kill carrier animals and ruin entire beef and milk-cow herds. It cannot be spread to humans. The disease virtually wiped out Taiwan's hog herds three years ago.

Kyonggi province, which surrounds South Korea's capital, Seoul, shut down its 11 livestock markets on Monday, and five other provinces farther south and east -- Kyongbuk, Kyongnam, Chonnam, Chungnam and Kangwon -- have ordered or planned to order the closure of a total of 106 livestock markets Tuesday.

Those account for 85 percent of all livestock markets in South Korea.

Meanwhile, a special government committee has been formed under the control of the prime minister's office to prepare for "a possible spread of the disease nationwide," the Agriculture Ministry said in a statement.

A total of 22 farms in South Korea's western region already have reported discovering signs of the disease, which was first found in late March on two farms in Paju, a major cattle-raising region north of Seoul.

Recent suspected outbreaks of the disease have also been reported in southern Japan's Miyazaki province.

Japan and South Korea have banned beef and pork imports from each other.

As a preventive measure, the Seoul government decided to inoculate all 11 million cattle and pigs in South Korea. As a first step, it ordered vaccines from Britain for 2 million cattle.

The cause of the disease has not been determined. But officials have speculated that the virus might have been transported in dust carried by winds from China. Some experts disputed that theory, saying the virus would have been killed by exposure to sunlight.

South Korean authorities sealed off infected areas and burned barns. Soldiers set up roadblocks and let vehicles through only after they were thoroughly fumigated.

Since the outbreak of the disease, meat consumption has dropped and exports suspended. South Korea last year exported 89,000 tons of pork to Japan. It exports little beef.

South Korea, consumed 395,000 tons of beef in 1999. It imported 153,000 tons from the United States, Australia, New Zealand and Canada.