N Korea will not invade S Korea: Kim Jong-Il

The official radio, a key North Korean propaganda tool, also said Seoul's plan to boost its self-defense capabilities was part of preparations for a northward invasion planned by the United States.

"There is a fuss in South Korea about a non-existent southward invasion threat, but what actually exists in our country is... a northward invasion threat," the radio quoted Kim as saying, according to Yonhap news agency.

The broadcaster did not give details, including when and where Kim made such remarks, said the South's news agency.

Radio Pyongyang accused the South of acting like "commandos" carrying out a US plan to invade the North.

North Korea has been locked in a tense row with the United States and its allies over its drive to produce nuclear weapons for more than two years.