Seoul, Oct 13 (IANS/EFE): North Korea Monday described the sending of balloons with propaganda leaflets by South Korean activists as "the worst obstacle" to improving relations and warned that it could trigger an armed confrontation.

The Rodong daily reported that the latest threat further raises concerns in South Korea about a military conflict after the North Korean military fired at the balloons sent aloft by activists from the other side of the border.

South Korean soldiers fired in return, although the incident did not escalate into a battle.

North Korea said that it would continue firing at the balloons.

In response, the South Korean defence ministry termed the action as provocative and pledged to respond harshly if Pyongyang again fired towards its territory.

Several South Korean civilian organisations regularly send balloons to the neighbouring country with news articles about international and domestic affairs, religious propaganda, chocolate bars and one dollar bills.

Although this has been going on for several years, over the past several weeks North Korea has taken them seriously and threatened to respond with an armed attack.

According to the Rodong daily, Pyongyang again urged Seoul to halt the balloons, describing the act as "reckless" and "hostile", and which impeded the development of bilateral relations.

In response, a South Korean government spokesperson said there was no legal framework to stop the balloons, although he said that measures would be taken to deal with the issue such as formally asking the activists to refrain.

Both Koreas recently agreed to meet for talks in late October or early November, but the issue of the balloons might lead to the meeting being cancelled.