A trash-carrying balloon is found in Namdong District, Incheon, in this photo provided by Incheon Fire Department, June 10. Yonhap

South Korea's military blared K-pop songs and news through its loudspeakers across the border with North Korea on Sunday as it stepped up its psychological campaign in response to North Korea's repeated launches of trash balloons.

The move came five days after Kim Yo-jong, the powerful sister of North Korean leader Kim Jong-un, warned of "gruesome and dear" consequences over continued leaflet campaigns seen by North Korea as psychological warfare.

North Korea has sent more than 2,000 trash-filled balloons into the South over nine occasions in a tit-for-tat retaliation for anti-Pyongyang leaflets that North Korean defectors in South Korea send to North Korea using balloons.

"As we have warned numerous times, we will conduct loudspeaker broadcasts in full-scale at all fronts starting from 1 p.m.," the Joint Chiefs of Staff (JCS) said in a notice to reporters.

The propaganda broadcasts typically comprise news, a message urging North Korean soldiers near the border to escape to South Korea as well as K-pop songs, including global K-pop sensation BTS' megahit singles "Dynamite" and "Butter."

Earlier in the day, South Korea partly operated loudspeaker broadcasts for the fourth straight day. The broadcasts began at 6 a.m. and are set to end 10 p.m., according to the JCS.

"The North Korean military's tension-escalating acts in front-line areas may lead it to pay a fatal price and we sternly warn that all responsibility for this situation lies with the North Korean regime," the JCS said, adding it is closely monitoring the North's activities under a robust South Korea-U.S. defense posture.

South Korean military soldiers dismantle loudspeakers in Paju, Gyeonggi Province, May 1, 2018. Korea Times file

Kim Yo-jong, vice department director at the ruling Workers' Party, said North Korea will inevitably change its method of responses if the defectors continue the leaflet campaigns against the North, the Korean Central News Agency (KCNA) reported Tuesday.

"We give the scum a stern warning again. They should be ready for paying a gruesome and dear price," Kim said in a statement carried by the KCNA.

In 2015, the two Koreas engaged in a brief exchange of artillery fire over the western part of their border over a propaganda loudspeaker campaign that Seoul resumed in retaliation for North Korea's land mine attack, which had maimed two South Korean soldiers. North Korea later expressed regret over the land mine attack and South Korea agreed to halt anti-Pyongyang broadcasts.

The JCS said Sunday that North Korea has again launched balloons presumed to be carrying trash toward South Korea. The latest balloons appeared to be traveling toward the northern part of Gyeonggi Province that surrounds Seoul, and the public were advised not to touch fallen balloons and to report them to the military or police.

South Korea resumed anti-Pyongyang broadcasts through its border loudspeakers on June 9 for the first time in six years. But it switched off the loudspeakers the next day in an apparent bid to prevent the situation from spiraling out of control.

On Thursday, South Korea restarted propaganda loudspeaker broadcasts toward North Korea in response to the North's repeated launches of trash-filled balloons into the South.

North Korea has bristled against the loudspeaker campaigns, as well as anti-Pyongyang leaflets, on fears that an influx of outside information could pose a threat to the Kim Jong-un regime.

In 2014, the two Koreas exchanged machine gun fire across the border after the North apparently tried to shoot down balloons carrying propaganda leaflets critical of North Korea.

North Korea blew up the inter-Korean liaison office in the North's border town of Kaesong in 2020 in anger over anti-Pyongyang propaganda leaflets sent via balloons by North Korean defectors in Seoul. (Yonhap)