South Korean activists Thursday launched tens of thousands of leaflets attacking North Korea`s regime towards the border, ignoring threats from Pyongyang and pleas from Seoul.

`Return the abductees!` shouted Choi Sung-Young as he released a towering gas-filled balloon carrying leaflets into the wind blowing towards the heavily fortified frontier.

Some 10 activists who gathered on a hillside outside Seoul said they plan to send 100,000 plastic pamphlets castigating the hardline communist regime and its leader Kim Jong-Il.

The launches have worsened already tense relations. Last week the North vowed to shut the border from December 1, a move that would cripple a major joint industrial estate developed at Kaesong as a symbol of reconciliation.

The Seoul government Wednesday appealed again for a halt to the leaflet war but says it has no laws to ban the launches.

On Thursday a police car and a military jeep followed a convoy of activists and reporters to the launch site west of Seoul but did not intervene.

Choi heads a group linking families of people abducted by Pyongyang in past decades, and has helped arrange the escape of some abductees.

`The South Korean people should understand and share the pain of the families of the abductees held in North Korea,` he told AFP.

Also involved in Thursday`s launch were the Fighters for Free North Korea (FFNK), a defector group.

Activists filled each giant balloon -- 10 metres (33 feet long) and one metre in diameter -- from bottles of hydrogen before releasing them and their cargo of leaflets into what they hope is a favourable wind.

One new leaflet depicts what it says is Kim`s family tree and suggests he has had nine wives or consorts.

Other pamphlets call for the overthrow of what they term a dictator and repeat claims he has suffered a stroke -- an especially sensitive topic.