PAJU, South Korea - Tensions flared Saturday as South Korean activists attempting to launch propaganda leaflets into the North were thwarted by egg-throwing residents of a border town, following threats of retaliation from Pyongyang.
Hundreds of riot police were deployed as the dispute erupted in the town of Paju, some 40 kilometres (25 miles) north of Seoul, when a dozen people with their faces hooded seized an activists' truck carrying balloons and leaflets.
Police also surrounded a bus carrying around 20 activists after local residents hurled eggs at it, shouting "Go back. Don't put our lives in danger!".
The activists had planned to release balloons carrying around 40,000 leaflets criticising the North's government across the heavily-militarised frontier.
But with Pyongyang threatening to retaliate over the launch, local residents set up road blocks with tractors and a placard reading "Stop anti-North leaflet launch jeopardising our lives!".
"We will become the victims of shelling if leaflets are scattered," read another placard put up in a tree.
The activists retreated after a two-hour protest during which they traded insults with the residents and chanted slogans such as "Let's terminate the dictatorship of (North Korean leader) Kim Jong-Un!".
However they did not abandon their attempt entirely, parking their bus on a road leading to the park with some insisting they should try again to float the balloons.
Later new leaflets were brought in by the activists, but local residents and liberal groups teamed up to foil their repeated attempts.
"Those instigated by North Korea ambushed us to block our event today but we will come back," Busan University professor Choi Woo-Won, the main organiser of Saturday's event, told reporters.
Despite Seoul's stance that the activists have a democratic right to launch the leaflets, police intervened to prevent a clash between activists and residents.
More than 1,000 riot police were deployed in and around the park, the South's Yonhap news agency said.
Pyongyang, which refers to the activists as "human scum", has long condemned the launches and in recent weeks has stepped up its demands for Seoul to ban the practice entirely.
Two weeks ago, North Korea border guards attempted to shoot down some balloons, triggering a brief exchange of heavy machine gun fire between the two sides.
"If a rash act of scattering leaflets slandering our dignity and system is taken again in South Korea, its consequences will be very grave," Rodong Sinmun, the North's official newspaper, said in a commentary on Saturday.
The North has warned that failure to halt future launches could scupper the planned resumption of high-level talks between the two Koreas.
The local residents in Paju insisted that the threats of military retaliation by North Korea are credible and that the activists are putting their lives and businesses at risk.
The South says there is no legal basis for a blanket ban, but it has urged the activists to exercise common sense and restraint.
Police have previously prevented the launches at times of high cross-border tensions, citing the possible dangers posed to local residents.