North Korea plans to restart propaganda loudspeakers along its entire border with South Korea within days, Kim Yo-jong announced on Thursday. Kim Yo-jong, sister of leader Kim Jong-un, made the statement through state news agency KCNA after inspecting border fortifications.

The move follows a deterioration in relations between the two countries. Kim Yo-jong had previously said on Wednesday that the loudspeakers would operate along the entire border from sometime in October.

Propaganda loudspeakers are a tool North Korea has used historically to broadcast messaging across the demilitarized zone separating the two nations. The announcement reflects escalating tensions on the peninsula.

The statement came through official North Korean channels without disclosure of the specific trigger for the timing decision or the content planned for the broadcasts. The Guardian reported the development Thursday.