A group of South Korean officials and workers visited a joint industrial complex on Tuesday, just days after the two Koreas agreed to fresh talks on reviving the shuttered site. About two dozen visitors from the South went to the Kaesong industrial complex -- a rare symbol of inter-Korea cooperation and a crucial source of hard currency for the North -- to restart power supplies, Seoul\'s unification ministry said. The trip follows months of friction and threats of war by Pyongyang after its February nuclear test attracted tougher UN sanctions, further squeezing its struggling economy. The visit is the first by southerners to the complex since early May. It was aimed at preparing for a visit on Wednesday by South Korean officials and dozens of businessmen who run factories at the industrial site. At the end of gruelling 15-hour talks, Seoul and Pyongyang said in a joint statement Sunday that they had agreed to let South Korean firms restart their shuttered plants at the complex near the border when conditions are ripe. The statement was viewed as a crucial step forward in winding down months of high tension, with the joint industrial zone seen as the last remaining symbol of cross-border reconciliation. Another round of talks to discuss conditions for reopening the site is scheduled for Wednesday. High on the agenda will be a demand from Seoul that the North guarantees it will never again unilaterally shut down the estate. The North, however, will likely find it hard to accept such a demand as it would amount to Pyongyang accepting full responsibility for the suspension. The complex -- built in 2004 about 10 kilometres (six miles) north of the border -- had previously remained largely resilient to turbulence in relations. But the North, citing military tensions and Seoul\'s hostility, pulled out all its 53,000 workers from the 123 Seoul-owned factories in April, prompting the South to withdraw the managers of around 120 companies in early May.