North Korea says it now considers the South as an enemy at war.
North Korea's Supreme People's Assembly has voted to scrap all agreements signed with South Korea on promoting economic co-operation as the two Koreas' relations continue to deteriorate sharply.
The assembly, which takes formal steps to adopt policy dictated by the ruling Workers' Party, also voted to abolish laws governing economic ties with Seoul, including the special law on the operation of the Mount Kumgang tourism project, the North's official KCNA news agency reported.
The tours to the scenic mountain just north of the eastern border were a symbol of an economic co-operation that began during a period of engagement between the two Koreas in early 2000s, drawing nearly two million South Korean visitors.
The project was suspended in 2008 after a South Korean tourist who strayed into a restricted zone was shot and killed by North Korean guards.
North Korea has said it now considers the South as an enemy at war and last year scrapped a military pact signed in 2018 aimed at de-escalating tension near the military border drawn up under a truce ending the 1950-53 Korean War.
South Korea's Unification Ministry, which handles ties with Pyongyang, said the North's action was not surprising and would only deepen its isolation.
Seoul does not recognise the unilateral move, an official added.
In a pre-recorded interview with state TV KBS aired late on Wednesday, South Korean President Yoon Suk Yeol called the shift in North Korea's inter-Korea policy "an extraordinary change" but said it was hard to understand the thinking behind the move.
"What hasn't changed is that the North has tried for more than 70 years to turn us into Communists, and while doing that, it realised its conventional weapons were insufficient so they went onto nuclear development to threaten us," he said.
Yoon, who has taken a hard line against Pyongyang, said he remains open to engaging the North, even by holding a summit meeting with Kim Jong-un and provide aid if it would help its economy.
However, he said the North Korean leadership is "not a rational group."
Since taking power in 2011, Kim has pushed the North to develop nuclear weapons and ballistic missiles of various ranges escalating tension with South Korea and the United States even as its economy languished.
KCNA separately reported that Kim on Wednesday toured factories producing consumer goods and food, and gave guidance on modernising the facilities as part of implementing a new regional development policy.