Activists in South Korea have sent propaganda leaflets to the North, a week after Pyongyang threatened military action over a similar launch.
The group floated 50,000 leaflets in several balloons from a park near the border town of Paju, watched by a heavy police presence.
Local residents trying to stop the move got into minor scuffles with activists.
Authorities prevented a similar launch last week after North Korea said it would respond with a "military strike".
Residents in the area concerned that Pyongyang would carry out its threat gathered to protest against the release of the balloons.
"Paju residents can't live properly due to worries. They come here way too frequently,'' a local shop owner, Kim Bok-nam, told Reuters news agency.
''Last time the North warned to directly strike here, so we came to protest since we can't tolerate it anymore.''
One of the activists, Choi Woo-won, dismissed the North's warning as "empty threats".
Activists - some of whom are defectors from North Korea - have sent leaflets on many past occasions. North Korea condemns the move but specific threats are rare.
Last week, however, Pyongyang threatened to fire on South Korean territory if activists went ahead with a launch.
South Korean authorities prevented the launch from taking place, as the military went into a state of alert and hundreds of residents were evacuated.
Tensions have been high on the Korean peninsula since the sinking of a South Korean navy ship in March 2010 which Seoul blamed on Pyongyang, and the shelling of a border island eight months later.
North and South Korea remain technically at war following the 1950-53 Korean War, which ended in an armistice. But North Korea has not fired on the Southern mainland since the end of the war.