South Korea said Tuesday that an outbreak of foot-and-mouth had spread to its mainland from an island west of Seoul despite a mass cull of livestock aimed at containing the disease.

Cattle at a farm in Gimpo, 30 kilometres (19 miles) west of Seoul, have tested positive for the highly contagious disease in the first outbreak outside of the epicentre on Ganghwa island, the agriculture ministry said.

Gimpo is a mainland region linked by a bridge to the island, where five cases have been reported since the disease was first detected on April 9.

Gimpo officials said Tuesday they immediately culled 194 cattle at the infected farm and three nearby farms, banning the movement of all 74,294 hoofed cloven animals at 362 farms within a radius of 10 kilometres.

Authorities already culled some 30,000 animals at 227 farms on Ganghwa to limit the spread of foot-and-mouth, which affects animals such as cattle, pigs, deer, goats and sheep.

The virus can spread rapidly between animals but is rarely transmitted to humans.

South Korea ordered a halt to pork and beef exports in January when an outbreak of the disease was confirmed in Pocheon, northeast of Seoul.

Outbreaks in 2000 and 2002 cost South Korea an estimated 450 billion won (400 million dollars).