The leader of South Korea's ruling party visited a South-run industrial zone in North Korea on Friday, as Seoul struggles to keep the key symbol of inter-Korean detente alive despite criticism it may help fund Pyongyang's nuclear ambitions. "I'm going to visit the Kaesong industrial complex today to let the world clearly know that the Kaesong and the Diamond Mountain projects should continue without being shaken even a bit," Rep. Kim Geun-tae, chairman of the ruling Uri Party, said in a statement ahead of his departure on the one-day trip. "We've put more than five decades of efforts to open this path and made a lot of sacrifices. If we imagine this path is closed again, people would well know what that would mean," he said, referring to the easing of tension that the economic projects have brought about across the world's most heavily armed border.