The explosion came just a week after the renegade country threatened to sever all inter-Korean roads and railways.
"North Korea blew up portions of the inter-Korean roads north of the Military Demarcation Line (MDL) on the Gyeongui and Donghae lines around noon," the Joint Chiefs of Staff (JCS) said.
"The South Korean military did not suffer any damage but responded by firing artillery as a warning shot in the area south of MDL," it added. "We are closely monitoring the North's further activities while maintaining firm surveillance in cooperation with the U.S."
The demolished roads were built as part of prior inter-Korean projects linking the two Koreas by land amid a thaw in inter-Korean relations. The Gyeongui line runs from Seoul to the North's Sinuiju on the Chinese border, while the Donghae line connects the east coasts of the two Koreas.
The incident was anticipated as North Korea vowed it would completely sever all roads and railways to the South as a "self-defensive measure," citing joint military drills between South Korea and the U.S.
Its hostile move intensified last week following allegations that South Korean drones were flying over Pyongyang, prompting threats of "catastrophic consequences."
Kim Yo-jong, the powerful sister of North Korean leader Kim Jong-un, warned last Saturday of "terrible consequences" if South Korean drones are detected again over Pyongyang. "The moment a drone from [South Korea] is found again in the skies over our capital, a horrible catastrophe will surely occur," Kim said in a statement carried by state media.
Inter-Korean tensions further escalated after South Korea dismissed the threats and warned that the North would face "the end of its regime" if it caused any harm to South Korea.
Tuesday's explosion prompted the government to designate approximately a dozen areas along the border and surrounding regions, including parts of Gyeonggi Province, as "danger zones" as a precautionary measure against possible provocations from North Korea. Military authorities also urged North Korean defectors and activist groups to stop sending propaganda leaflets across the border.
In June 2020, the North blew up a cross-border liaison office in Kaesong that had been refurbished with billions of South Korean taxpayers' money.
