South Korea’s military reported on Monday that they are observing indications of North Korea installing its own loudspeakers along their heavily fortified border. This follows the South’s decision on Sunday to resume anti-Pyongyang propaganda broadcasts through its speakers for the first time in several years, marking a return to Cold War-style psychological warfare between the two nations.

The South’s resumption of loudspeaker broadcasts was a direct response to North Korea’s recent actions of sending and manure across the border over the past few weeks. North Korea has characterized its balloon campaign as a countermeasure to South Korean civilian groups using balloons to distribute anti-North Korean propaganda leaflets over the border. Pyongyang has consistently condemned such activities, demonstrating its extreme sensitivity to any external criticism of leader Kim Jong Un’s authoritarian regime.

This escalating exchange involving speakers and balloons has further exacerbated tensions between the Koreas, coinciding with the ongoing stalemate in talks regarding North Korea’s nuclear ambitions.

During their latest nuclear planning discussions in Seoul, U.S. and South Korean officials reviewed an undisclosed guideline outlining their nuclear deterrence strategies to address the growing threats from North Korea. They also discussed strengthening the allies’ combined , according to participants at the news conference.

Cho Chang-rae, South Korea’s deputy defense minister for policy, and Vipin Narang, acting U.S. assistant secretary of defense for space policy, declined to offer specific assessments when asked to comment on the threat posed by North Korea’s balloon activities.

Seoul’s Joint Chiefs of Staff did not immediately provide details regarding the number of suspected North Korean speakers or their locations along the border. They stated that the speakers remained silent as of Monday afternoon.

On Sunday, South Korea activated its loudspeakers for an initial broadcast directed at North Korea, which reportedly included news, criticism of North Korea’s government, and South Korean pop music.

Several hours later on Sunday, Kim Jong Un’s powerful sister issued a warning, stating that the South had created a “prelude to a very dangerous situation.” She asserted that South Korea would face an unspecified “new response” from the North if it continued with the broadcasts and failed to halt civilian activists from flying anti-North Korean propaganda leaflets across the border.

“I sternly warn Seoul to immediately cease its dangerous activities that would further provoke a crisis of confrontation,” Kim Yo Jong stated through state media.

Lee Sung Joon, spokesperson for South Korea’s Joint Chiefs of Staff, described Kim’s comments as an escalated verbal threat but did not provide a specific assessment of the actions the North might take. Lee assured that the South was conducting broadcasts in locations where soldiers have adequate protection and are equipped to swiftly retaliate in case of an attack.

“(We) don’t think that they could provoke us that easily,” Lee stated during a briefing on Monday.

The Joint Chiefs of Staff did not specify the border area where Sunday’s broadcast took place or the content of the messages transmitted over the speakers. They indicated that any subsequent broadcasts are “entirely dependent on North Korea’s behavior.”

The South removed loudspeakers from border areas in 2018, during a brief period of engagement with the North under Seoul’s previous liberal government.

In deciding to restart the loudspeaker broadcasts, South Korea’s presidential office criticized Pyongyang for attempting to cause “anxiety and disruption” in the South and emphasized that North Korea would be “solely responsible” for any future escalation of tensions.

North Korea attributed its balloon campaign to South Korean activists’ actions of sending over balloons containing anti-North Korean leaflets, as well as USB sticks loaded with popular South Korean songs and dramas. Pyongyang is highly sensitive to such materials, fearing they could demoralize front-line troops and residents, potentially weakening leader Kim Jong Un’s hold on power, according to analysts.

In 2015, when South Korea reactivated loudspeaker broadcasts for the first time in 11 years, North Korea fired artillery rounds across the border, prompting South Korea to return fire, according to South Korean officials. No casualties were reported.