SEOUL - Republic of Korea(ROK) said Monday it will not accept unilateral measures announced by the Democratic People's Republic of Korea (DPRK) to dispose of all ROKn properties at a mountain resort jointly managed by the two Koreas.

In a statement carried by the state media, the DPRK said that it believes ROK "totally abandoned the protection of property and interests of enterprises" and vowed to dispose of all assets of ROK's people at the Mount Kumgang resort.

The DPRK also ordered all ROK's nationals to leave the mountain resort within 72 hours.

The measures, following Pyongyang's seizure of ROK's nationals- owned properties, are seen as Pyongyang's response to Seoul's reluctance to resume the suspended tours, once a rare source of hard currency for the cash-strapped country.

The assets subject to the planned disposal, including restaurants and a golf course, are believed to be worth $325.5 million. Previous visits to the resort by ROK's businessmen at the request of the DPRK failed to break the impasse over the threatened disposal.

"The government cannot accept North Korea (DPRK)'s arbitrary measures, and we'd like to make it clear the North should be held responsible for all consequences," Chun Hae-sung, spokesman for the unification ministry in Seoul, told reporters.

"The government will seek all necessary measures including legal and diplomatic ones, and will stay in close contact with business operators involved," he added, calling Pyongyang's announcement "regrettable." The ministry oversees inter-Korean affairs.

The lucrative tours to the scenic mountain just north of the border between the two Koreas, launched in 1998 amid a growing rapprochement, were suspended in 2008 after a ROK's tourist was shot dead for alleged intrusion of a restricted military zone.

Seoul has refused to reopen the tours without a proper investigation into the incident and safety guarantees, with the unification ministry recently saying the tragedy lies "at the core of the current dispute."

Pyongyang, claiming it has done enough, terminated in April its exclusive deal with Hyundai Asan, a Seoul-based tour operator, and announced its plan to develop the area into a special zone for international tours.

Hyundai Asan officials on Monday reportedly called on the DPRK authorities to withdraw the measures and urged the two Koreas to resume the ill-fated tours. The company, part of ROK's nationals conglomerate Hyundai Group, had invested tens of millions of dollars into the project.

Fourteen ROK's nationals at the resort area are expected to return home by Wednesday.