South Korea’s Unification Minister Kim Yeon-chul said the blast took place in the North Korean border town of Kaesong at 2:49 pm local time on Tuesday.
It came shortly after the North Korean army threatened action against the rival South over the propaganda campaign.
“Our army will rapidly and thoroughly implement any decisions and orders of the Party and government,” the General Staff of the Korean People’s Army (KPA) said in a Tuesday statement carried by North Korea’s state news agency KCNA.
The General Staff said it had been reviewing an “action plan” to reenter zones that had been demilitarized under a 2018 inter-Korean pact and “turn the front line into a fortress.”
The development comes amid heightened tensions between the two Koreas over the leaflets, which are sent into the North usually by balloon over the border or in bottles by river.
Defector-led groups in the South have regularly sent anti-Pyongyang publicity flyers, along with food, US one-dollar bills, mini radios, and USB sticks containing South Korean TV shows and news clips.
Pyongyang has warned the South several times recently to stop the propaganda campaign and has already severed two valued hotlines with Seoul.
Responding to Pyongyang’s reaction, the South Korean Defense Ministry urged North Korea to abide by the 2018 agreement, in which the militaries of the two countries pledged to cease “all hostile acts” and dismantle a number of structures along the heavily fortified Demilitarized Zone between their borders.
But it said Seoul was taking the situation seriously.
“We’re taking the situation seriously,” said the ministry’s spokeswoman, Choi Hyun-soo, at a press briefing. “Our military is maintaining readiness posture to be able to respond to any situation.”
On Saturday, the North Korean leader’s sister, Kim Yo-jong, who serves as a senior official of the ruling Workers’ Party, said she had ordered the country’s military to prepare for unspecified “next action.”
Seoul has recently taken legal action against the defector-led groups. In their lawsuit, South Korean authorities said the actions of the groups fuel cross-border tensions, pose risks to residents living near the border, and cause environmental damage.
The anti-Pyongyang groups, however, have insisted that they are determined to press ahead with the propaganda campaign throughout the week.