A group of South Korean lawmakers crossed the fortified border into North Korea Wednesday to visit a jointly-run industrial park that recently reopened after military tensions caused a five-month closure.
The rare cross-border trip by 21 parliament members comes as the two Ko¬reas are struggling to build momentum behind a series of stop-start confidence-building measures.
They visited four South Korean companies with factories in Kaesong, which lies 10 kilometers inside North Korea and was established in 2004 as a symbol of inter-Korean cooperation.
The lawmakers were joined by officials from the South's Unification Ministry, including Vice Minister Kim Nam-sik. They did not meet with North Korean officials in Kaesong.
At talks with South Korean businessmen, ruling party parliament member Ahn Hong-joon said that despite Kaesong's reopening, many companies still have a hard time securing new orders, according to a report carried by the Yonhap news agency.
"The governments of South and North Korea should work together for the sustained development and stability of the Kaesong Industrial Complex," he said.
Ahn urged the North to accelerate discussion with the South on turning Kaesong into a viable industrial zone.
North Korea effectively shut down the complex in April by withdrawing its 53,000 workforce during a sharp spike in military tensions that followed the North's third nuclear test in February.
The two Koreas agreed last month to resume operations, but talks on reforming the way Kaesong is managed have shown little progress, and the South Korean firms say production is only at 80 percent capacity.
South Korea is keen to bring in foreign investors, but it recently cancelled a planned investment roadshow, citing a lack of progress in the talks with the North.
Earlier this month, Pyongyang threatened "all out war" following a two-day drill involving a US nuclear-powered aircraft carrier alongside South Korean and Japanese vessels began off the southern coast of the Korean peninsula.
Tensions on between the North and South have been blowing hot and cold for months.
The reopening of Kaesong had initially promised to herald a wider thaw in cross-border ties and was followed with an agreement to hold a reunion for family members separated by the 1950-53 Korean War.
But Pyongyang cancelled the event at the last minute, partly in anger at Seoul's reticence about resuming tours to the North's Mount Kumgang resort.
"I hope this visit to Kaesong will help resume the family reunions and revive tours to Mount Kumgang and other economic exchanges," opposition lawmaker Shim Jae-won said earlier.