Scuffles broke out in a South Korean border town Saturday between activists planning to send propaganda leaflets into North Korea and town residents who wanted to stop them.
The activists planned to release balloons carrying the leaflets critical of Pyongyang's government into North Korea, as they had done earlier this month.
About 1,000 police officers had been dispatched to the border town.
The North has warned that failure to halt the launches could scupper the planned resumption of high-level talks between the two Koreas.
Paju residents say the threats of military retaliation by North Korea are credible and that the activists are putting the residents' lives and businesses at risk.
The South says it cannot legally prevent the demonstrators from exercising their freedom of expression.