South Korea plans to increase diplomatic pressure on North Korea over human rights issues, including the case of three people from the South believed to have been held in the communist nation for decades, a senior official said Friday. The move could further exacerbate the already frayed relations between Seoul and Pyongyang. An immediate focus of the campaign is expected to be on the case of Shin Suk-ja and her two daughters who are believed to have been held in the North since 1987, a year after her husband, Oh Kil-nam, fled the communist nation, South Korean News Agency (Yonhap) reported