Seoul  - North Korea's military threatened Monday to quit an industrial cooperation project if South Korean activists do not stop dropping propaganda leaflets in its territory.

The North urged the South in a meeting between military officers from both countries to put a stop to the leaflet distribution, the South Korean Foreign Ministry said. The meeting took place on the border between the two countries near the town Paju on South Korea's west coast.

Pyongyang complained at the gathering at the inter-Korean border that the leaflet drops by South Korean organizations was increasing.

A ministry spokesman said the North threatened to close down a jointly operated business park in the North Korean border town Kaesong should the drops continue, repeating warnings voiced at talks three weeks ago.

The Kaesong industrial park is regarded one of the most visible signs of growing ties between the two Koreas.

Meanwhile a representative of a group of families of South Koreans believed to have been abducted by the North, said they again sent more than 40,000 helium ballons with leaflets into North Korea.

The leaflets mentioned the alleged health problems of North Korean leader Kim Jong Il and asked North Koreans to rise up against the regime in Pyongyang, Choi Sung Yong said.

North Korea on Monday called on the South to repair existing military communication links between the two countries, officials in Seoul said. South Korea should also deliver equipment for modernizing North Korea's communication network, as promised in an agreement last year.

Bilateral relations have taken a downward turn since the conservative government of President Lee Myung Bak came too power in South Korea in February. Lee has pursued a stricter course against Pyongyang than his liberal predecessors.

High-level talks between the North and South have been mothballed by Pyongyang after Lee took office. (dpa)