SEOUL (Reuters) - A group of South Korean businessmen who own factories in the Kaesong industrial complex inside North Korea said on Wednesday they want to visit to verify the North s claim that it had restarted some operations there on its own. South Korea pulled out of the joint venture last year in response to the North s nuclear and missile tests, ending more than a decade of cooperation at the factory park, on the North s side of the demilitarized zone (DMZ), that was the last remaining symbol of inter-Korean cooperation.  North Korea s state-run web sites said on Friday North Korean workers were operating in the district, adding that it was  nobody s business what we do in an industrial complex where our nation s sovereignty is exercised . The South Koreans said they would ask the Ministry of Unification for permission to visit.  South Koreans have to obtain approval to contact North Koreans or travel in the country. The two sides are technically still at war after their 1950-53 conflict ended in a truce, not a treaty.   We urge the North to immediately halt the operation of any of our corporate assets,  said Shin Han-yong, the leader of the group, who used to operate a plant making fishing nets in Kaesong. In recent weeks, North Korea has launched two missiles over Japan and conducted its sixth nuclear test, a sign that it may be fast advancing toward its goal of developing a nuclear-tipped missile capable of hitting the U.S. mainland. U.S. Secretary of State Rex Tillerson said last weekend that Washington was directly communicating with the North on its weapons programs but that it had shown no interest in dialogue. When the South suspended the operations at the industrial park, it said the North had diverted wages paid to its workers by South Korean firms to fund its nuclear and missile programs. But in July, two months after liberal President Moon Jae-in was elected in the South, a government official said there was no hard evidence to back up the assertion. Moon had initially sought to engage North Korea in talks and cooperation, but current political tensions have tied the president s hands. Despite military tension, the businessmen s visit, if it comes off, may provide a chance to restart talks with the North, Shin said.  We don t know if the North will accept our trip at a time when it only sees the U.S. as its dialogue partner, but we are pinning our hopes on a one in ten chance that may exist,  he said. 