A boar with African swine fever has been found dead in the demilitarised zone (DMZ) that separates the two Koreas.
The virus was only discovered in South Korea recently, and there was speculation it arrived via pigs crossing the heavily-guarded DMZ.
North Korea first recorded ASF in May, and the South made great efforts to keep it out, including border fences.
Despite its name, the DMZ is one of the world's most fortified places.
It is a 4km-wide (2.5 miles) strip of land, laden with landmines, that is a buffer zone between North and South Korea.
More than 10,000 pigs have died or been culled in the South since ASF was discovered. More than six million pigs have been culled overall in Asia.