Seoul - North Korea threatened Wednesday to close its borders with South Korea starting December 1, accusing Seoul of pursuing a confrontational policy against its neighbour.

North Korea would "strictly restrict and cut off all the overland passages" at the inter-Korean border, said a statement distributed by the country's official Korean Central News Agency.

"The South Korean puppet authorities should never forget that the present inter-Korean relations are at the crucial crossroads of existence and total severance," Pyongyang warned.

North Korea's decision to shut their border with South Korea is "regrettable" and would have a negative impact on inter-Korean relations, a ministry official in Seoul said Wednesday.

"North Korea's announcement that it will take measures to limit passage across the border is regrettable," Kim Ho Nyoun, spokesman for the Unification Ministry, said in a statement.

While the ministry was hopeful that North Korea would return to dialogue with Seoul, the spokesman said that if the threat was carried through "it will have a negative impact on efforts to improve inter-Korean relations."

The North Korean army said the "actual crucial measure" was taken in retaliation for the South's failure to abide by existing agreements made at summits in June 2000 and October 2007.

"The South Korean authorities are getting frantic in their racket for confrontation with the DPRK while paying lip-service to respect for the June 15 joint declaration and the October 4 declaration ... and resumption of dialogue for implementing them," the North Korean military's message said, referring to North Korea by the acronym of its official name, the Democratic People9s Republic of Korea.

In 2000, the leaders of North and South Korea held their first summit, issuing a declaration on eventual peaceful reunification, confidence-building measures and economic cooperation. In 2007, a second declaration was signed to establish a permanent peace mechanism.

The two countries remain officially at war after the 1950-53 Korean War, which ended with a truce and not a peace treaty.

"... The racket of confrontation with the DPRK kicked up by the South Korean authorities, including the military in particular, is going beyond the danger level despite its repeated warnings," the North's message said.

The communist state has recently stepped up verbal attacks against the South, repeatedly threatening to cut all ties. Relationships between the two Koreas have cooled markedly since a conservative government took office in Seoul in February which pledged to link inter-Korean relations to the North's nuclear disarmament.

Relations took a further dip as Pyongyang accused Seoul of not preventing South Korean activists from releasing balloons carrying propaganda leaflets near the border.

A full border shutdown would also affect cooperation projects like an industrial park just over the border near the North Koran city Kaesong and tourism, both important sources of income for the impoverished North.

Under South Korea9s two previous administrations the two Koreas agreed to allow visits by families separated by the Korean War and inter-Korean border, hold ministerial and military talks, establish a joint industrial park, allow South Korean tourists to visit designated areas in the North and open regular rail service over the border, which began in December.

The Unification Ministry spokesman in Seoul said it was not clear whether the North meant to close the border completely, adding that the threat was open to interpretation. "We don't think it means complete closure," he said. (dpa)