North Korea is threatening to confiscate property owned by South Korean firms within the North’s Mount Geumgang resort in an apparent move to force the South to restart stalled tour programs to the scenic mountain.

The North made the notification in a notice sent by the Asia-Pacific Peace Committee on Thursday to the South Korean operator of tour programs to the area, Hyundai Asan.

The North demanded South Korean real estate owners visit the North by next Thursday for a probe into the suspended tour programs, adding that in the event the property owners fail to respond to the North’s summons, the owners will face serious penalties, including possible confiscation of property.

The North added that it will seek to launch tourism projects with other business partners starting next month if Seoul continues to suspend tourism programs to the North’s Mount Geumgang and Gaeseong.

Currently, some 40 South Korean firms, including Hyundai Asan and the Korea Tourism Organization, possess real estate at the North’s Mount Geumgang resort. Such firms’ investments in the area are estimated to be valued at some 360 billion won.

In Seoul, the government expressed deep regret over the North’s notification, saying the move goes against not only agreements reached between business partners but also between the two Koreas. The government said it would approve visits to the North by the property owners.