S Korean activists launch anti-Pyongyang leaflets

South Korean activists launched tens of thousands of anti-Pyongyang leaflets into North Korea on Saturday, amid heightened tensions on the divided peninsula, using a propaganda tool that usually sparks threats of reprisals.

Conservative activists, including many North Korean defectors, have been carrying out leafleting exercises using giant gas-filled balloons for years.

Defector-turned-activist Park Sang-Hak and his colleagues released 50,000 leaflets tied to three large balloons from an empty field near Paju City close to the border with North Korea, marking the sixth anniversary of the sinking of a South Korean warship with the loss of 46 sailors.

Seoul pinned the blame for the sinking on the North and froze trade and investment ties.

One of the three balloons was strung with a large banner printed with a Pyongyang-published picture of leader Kim Jong-Un smiling against the backdrop of a missile being assembled.

"Bring down a firestorm on nuclear maniac Kim Jong-Un", read the slogan.

"We plan to launch a total of 10 million leaflets into the North over the next three months condemning North Korea's nuclear tests", Park told journalists.

In October 2014, North Korean frontier guards attempted to shoot down a set of such balloons, triggering a brief exchange of fire across the border.

Park and other activists face protests by residents and merchants living near the border, who are concerned that their livelihood might be affected.

Since North Korea's fourth nuclear test on January 6, South Korea has resumed blasting a mix of K-pop and propaganda messages into the North, using giant banks of speakers on the heavily militarised border.

North Korea has responded by dropping its own leaflets over the border, attacking South Korean President Park Geun-Hye and returning to psychological warfare methods used in the 1950s and 1960s.