North Korea dropped nearly one million propaganda leaflets into South Korea with helium balloons, said Seoul officials said Monday.
The move has increased the ongoing tension between Pyongyang and Seoul over the North's claim on Jan. 6 that it had tested a miniaturised hydrogen nuclear device.
Seoul started anti-Pyongyang audio propaganda with broadcasts and K-pop songs from border loudspeakers.
North Korea quickly responded to this by resuming its own border broadcasts and floating the balloons through moving anti-South leaflets, said Seoul officials.
Seoul's Defense Ministry Spokesman Kim Min-seok announced that the leaflets reached Seoul.
However, South Korean activists have also sent propaganda balloons from time to time.
South Korean officials think their broadcasts will annoy the tightly controlled, authoritarian country by disturbing troops and public.
There are doubts in South Korea that the North Korean propaganda leaflets will have any effect on the people in the more wealthy regions of South Korea.
The two Koreas share the most heavily reinforced border in the region since their war in the early 1950s ended with a ceasefire, not a peace agreement.
Approximately 28,500 US troops are deployed in South Korea as a means of deterring North Korea.