North Korea's KCNA news agency reported on October 17 that roads and railways connecting to South Korea are now completely blocked after Pyongyang blew up inter-Korean roads on October 15.
Pyongyang calls the blowing up of these border lines a legitimate action against a hostile state as defined in the Constitution.
A 60-meter stretch of roads and railways at the border has now been completely blocked in the phased separation of North Korea's territory from South Korea, KCNA reported.
"This is an inevitable and legitimate measure taken in accordance with the requirements of the DPRK's Constitution, which clearly states that South Korea is a hostile state," KCNA news agency said.
North Korea's state news agency also quoted a spokesman for the Ministry of National Defense as saying that Pyongyang will take further steps to firmly fortify its southern border.
In January this year, North Korean leader Kim Jong-un called for a constitutional amendment that would remove the goal of unification with South Korea and clearly define North Korea's territorial borders.
Last week, the Supreme People's Assembly, North Korea's legislative body, met for two days, with the aim of amending the Constitution to officially designate South Korea as a separate country and its main enemy. North Korean state media has not reported on the specific results of the meeting.
South Korea has declared its policy of continuing to pursue unification but will respond with force if North Korea takes any aggressive action.
In recent days, North Korea has accused South Korea of violating its airspace with drones and vowed to retaliate. The South Korean government has refused to comment on whether its military or civilians are involved in flying the drones, as North Korea has alleged.
South Korean military fired warning shots on October 15 in response to North Korean road and rail explosions.
Last week, Pyongyang announced it was completely cutting off inter-Korean roads and railways and fortifying the border area in an effort to push for the abolition of the goal of unification on the Korean peninsula.
Tensions between the two Koreas have escalated since last year, when both sides declared a 2018 agreement aimed at easing military tensions no longer valid.
