North Korea blows up parts of Donghae road connected to South Korea, in this picture captured from footage provided by South Korea's Joint Chiefs of Staff, Oct. 15. Yonhap

North Korea on Tuesday blew up roads connected to South Korea once seen as symbols of inter-Korean cooperation as it seeks to cement its animosity toward the South, which it regards as a "primary foe."

"The North Korean military conducted detonations, assumed to be aimed at cutting off the Gyeongui and Donghae roads, at around noon and is carrying out additional activities using heavy equipment," the Joint Chiefs of Staff (JCS) said in a text message to reporters.

The JCS said the South's military did not suffer any damage and that it responded by firing shots south of the Military Demarcation Line (MDL) as a means of self-defense and as a warning against acts that likely violate the Armistice Agreement.

"The military is closely monitoring the North Korean military's activities and maintains a firm readiness posture amid strengthened surveillance under South Korea-U.S. cooperation," it added.

The detonations took place in areas just 10 meters away from the MDL at 11:49 a.m. on the road along the Gyeongui line and at 12:01 p.m. on the road along the Donghae line, respectively, affecting land routes measuring tens of meters, a JCS official said.

Last week, the North's military announced a plan to "completely separate" North Korea's territory from South Korea, saying it had informed the U.S. military of the move to "prevent any misjudgment and accidental conflict."

This picture shows a road leading toward North Korea in Goseong County, Gangwon Province, Oct. 9. Yonhap

The Koreas are connected by roads and railways along the Gyeongui Line, which connects the South's western border city of Paju to the North's Kaesong, and the Donghae Line along the east coast.

The move came as North Korea has been ramping up inter-Korean tensions and wiping out traces of unification after its leader Kim Jong-un defined the Koreas as "two hostile states" late last year, with the country taking steps to dismantle inter-Korean land routes.

The North has since removed street lamps and installed mines along its side of the Gyeongui and Donghae roads, as well as deploying troops to build apparent anti-tank barriers and reinforce barbed wire within its side of the Demilitarized Zone separating the two Koreas.

Last week, JCS Chairman Adm. Kim Myung-soo told lawmakers that the Gyeongui and Donghae routes had been effectively cut off in August, noting that the military had been monitoring the North's activities.

A JCS official projected that North Korea may build concrete walls over the roads where the explosions took place but said it is unlikely that the North may stage another "show" to demonstrate its push to eliminate signs of unification.

"Blowing up the inter-Korean roads may be its final show as it has already destroyed other visible signs of inter-Korean cooperation, such as the inter-Korean joint liaison office," the official said.

In 2020, North Korea blew up the inter-Korean joint liaison office in its border town of Kaesong after lashing out at the South for failing to stop North Korean defectors in South Korea from sending anti-Pyongyang leaflets across the border via balloons.

The official said the North apparently aimed to shore up internal unity by showing its residents that all ties between the Koreas have been severed, while warning the South that ties between the two Koreas are no longer viable.

Tensions have further heightened after North Korea claimed Friday that the South had sent drones over Pyongyang three times this month. Kim Yo-jong, the influential sister of the North Korean leader, warned the following day of a "horrible disaster" if South Korean drones are flown again over the North's capital.

South Korea has neither confirmed nor denied the claim and warned that the North will see "the end of its regime" if it causes any harm to South Koreans. (Yonhap)