North Korea is undertaking a large-scale purge of top officials including Kim Chong-u, responsible for the country's first special economic zone, a South Korean researcher has confirmed. Yu Kun-kol, a research fellow at the Seoul Sinmun International Strategic Affairs Institute, wrote in South Korea's Seoul Sinmun newspaper that the purge started early this year. It had claimed officials responsible for ties with the South, foreign trade and investment. Diplomatic sources also said that several officials had recently been executed in Pyongyang on corruption charges. Kim Chong-u was disciplined and purged in February by North Korean leader Kim Jong-il for his poor performance in developing the Raijin-Sonbong free trade zone, the paper reported. He was the chairman of the Committee for the Promotion of External Economic Co-operation. Many officials also linked to the South Korean scandal over collusion between the South's Central Intelligence Agency and the North have reportedly been dismissed. These include An Pyong-su, vice-chairman of the North Korean Committee for the Peaceful Reunification of the Fatherland, Chon Kum-chol, vice-chairman of the North Korean Asia-Pacific Peace Committee, Chae Yong-hae, head of the Youth League, and Chang Song-taek, first vice-director of the Organisation and Guidance Department of the Korean Worker's Party. The report added North Korea's ambassadors to Russia, Denmark, Yugoslavia, Yemen, Jordan, Zambia and Senegal had been replaced.