South Korea on Tuesday confirmed a fourth case of African swine fever(ASF) in the country, spurring concerns over a nationwide spread of the highly contagious animal disease.

The Ministry of Agriculture, Food and Rural Affairs said that a suspected case reported Monday afternoon at Paju, located near the border with North Korea, resulted in a positive test for the virus.

The farm, which is raising 23-hundred pigs, is located about seven kilometers away from a farm in Yeoncheon which reported the second confirmed ASF case last week.

The latest case is the second confirmed case in Paju alone, raising the number of outbreaks of the disease to four in a week.

Earlier on Monday, the ministry confirmed a third case in Gimpo, the first from a region south of the Han River, which runs through Seoul, adding to woes over a possible nationwide outbreak of the disease.

The agriculture ministry issued a 48-hour standstill for pig farms, feed factories, slaughterhouses and vehicles for Gyeonggi Province, Incheon and Gangwon Province starting from 7:30 p.m. Monday.