SEOUL (AFP) - The planned resumption of high-level talks between North and South Korea later this week appeared in jeopardy on Monday with Pyongyang refusing to confirm its participation.

The two Koreas agreed earlier this month to restart the dialogue, and South Korea had proposed meeting on Oct 30.

However, in the latest in a series of similarly themed messages, North Korea said on Sunday it was being forced to reconsider taking part in the talks due to a perceived lack of sincerity on the South's part.

The faxed message from the powerful National Defence Commission specifically cited the South's refusal to ban activists launching balloons over the border with bundles of anti-North leaflets. "We have to think again about whether high-level contact can be held in such a mood," it said.

On Monday, the North Korean ruling party's official newspaper, the Rodong Sinmun, urged Seoul to cease all "hostile acts", including the leaflet launches, and warned that cross-border relations were "inching close to confrontation".

The South's Unification Ministry said Seoul had responded on Monday, saying it remained committed to resuming the dialogue and urging the North not to make the issue of leaflet launches a pre-condition.

"We also urged North Korea to clarify its position on our proposal for talks on Oct 30," ministry spokesman Lim Byeong-Cheol told a press briefing.

Pyongyang has long condemned the leaflet launches and refers to the activists involved as "human scum".

In recent weeks it has stepped up its demands for Seoul to ban the practice entirely, but the South insists the activists have a democratic right.

A leaflet-launching operation near the border on Saturday saw activists clash with egg-throwing local residents, who argue that the events place them at risk of North Korean retaliation.

After a stand-off monitored by a heavy police presence, the activists, who had planned to launch around 50,000 leaflets, were forced to retreat.

Although the North Korean message acknowledged that the main launch event was scrapped, it noted that the South Korean authorities had failed to prevent the activists relocating to another site further from the border and releasing one balloon in the evening.

The original agreement to resume a dialogue came during a surprise visit to the South by a top-ranking North Korean delegation earlier this month.

The last round of high-level talks was held in February and resulted in the North hosting a rare reunion of families separated by the Korean War.