Pyongyang demanded today that Seoul repatriate nine North Korean nationals who defected to the South last weekend, according to Yonhap News Agency.

The nine defectors are reported to have arrived on the South Korean island of Udo, after braving the Yellow Sea frontier in a paddleboat.

International human rights organizations report that defectors face death, torture and prison upon repatration to their native North Korea.

Earlier this year, 31 North Korean fishermen accidentally crossed into South Korean territory. Four of the North Korean nationals expressed a desire to stay in South Korea, and only 27 were repatriated, despite Pyongyang's call that they all be repatriated.

North Korean national television broadcast calls for the four remaining crew members to return home and aired announcements that Seoul was holding them against their will.

There are two routes available for North Koreans defecting to the South. Defectors either brave the harsh winds and waves of the Yellow Sea or cross the Yalu River into northern China, eventually settling there illegally-- integrating into China's ethnic Korean communities-- or heading for Seoul to apply for political asylum.

There are currently some 21,000 North Korean defectors in South Korea alone, Yonhap Agency reports.

Pyongyang sees the defectors as a major blow to its national image, in both the domestic and international spheres.

Last month, 14 illegal aliens were arrested near the Chinese-North Korean border, in a gesture of cracking down on the countless North Korean defectors to China's Northeast.

The more recent group of defectors has arrived in the South at a time of escalating tensions between the two Koreas.

Of late, North Korea has issued a series of statements, promising an impending attack on the South and ruffling feathers in Seoul.

The South Korean Defense Ministry has announced that North Korea has had enough time to develop miniature nuclear arms since its first nuclear detonations in 2006.

The ministry also announced that North Korea was building a second, more sophisticated long-range missile launch site.

Seoul worries that a light-weight nuclear technology could be strapped to a missile and lobbed into South Korean territory, causing great destruction and provoking another military face-off between the two Koreas.