Seoul - Communist North Korea stepped up pressure on its southern neighbour, threatening Thursday to cut all ties with Seoul, South Korean media reported.

Pyongyang reiterated its accusations that the conservative government of President Lee Myung Bak was following an aggressive policy against the North in a commentary run by the Rodong Sinmun newspaper, a North Korean government mouthpiece.

"If the group of traitors keeps to the road of reckless confrontation with the DPRK, defaming its dignity despite its repeated warnings, this will compel it to make a crucial decision including the total freeze of the North-South relations," Rodon Sinmun wrote, referring to North Korea by the acronym of its official name, the Democratic People's Republic of Korea.

Relations between the two Koreas have deteriorated since Lee took office in February. In contrast to his liberal predecessors, Lee embarked on a harsher course versus the regime in Pyongyang, announcing a review of planned cooperation projects and linking aid to North Korea's cooperation in nuclear disarmament efforts.

North Korea froze high-level government dialogue as a reaction.

Pyongyang's latest warning shot came amid expectations of improving relations with the United States. Washington removed the communist state from a terrorism blacklist after North Korea agreed to allow international inspectors to verify its nuclear weapons programme. (dpa)