Hundreds of South Korean businessmen rallied Wednesday near the border with North Korea, urging the swift resumption of operations at their abandoned plants in a shuttered inter-Korean industrial zone.

The protest came amid signs that South Korea is considering permanently withdrawing from the Kaesong complex, which was closed in April as military tensions surged across the Korean peninsula.

Seoul is preparing to pay insurance claims to companies with investments in the 123 South Korean firms located in Kaesong -- a move widely seen as a prelude to a permanent shutdown.

The two Koreas have held six rounds of fruitless meetings on Kaesong's future, and on Sunday the South said it was "reaching the limit" of its patience.

On July 28, Seoul proposed a "final" round of talks to resolve the issue, but Pyongyang has yet to respond.

At Wednesday's hour-long rally in Paju near the border, some 500 people including representatives from the Kaesong-based companies urged both sides to reach a swift agreement to reopen the zone.

Labelling Kaesong a "symbol of peace", they called on North Korea to accede to the South's request for a binding guarantee to avoid any unilateral shutdown of the complex in the future.

They have also urged Seoul to show more "flexibility" in its negotiations with Pyongyang.

Set up just north of the border in 2004, Kaesong had survived previous inter-Korean crises, but eventually fell victim to two months of elevated tensions following a nuclear test by the North in February.

In early April, the North withdrew all its 53,000 workers who produced textiles and other goods at the Kaesong plants.

The North has rejected the South's demands for a guarantee, saying it would be tantamount to accepting responsibility for the Kaesong shutdown.

Pyongyang says the decision to pull out its workforce was the direct result of military intimidation from South Korea as it held joint military exercises with the United States.