The government says that, despite North Korea's threat of military action, no unusual moves have been detected in the North and that South Koreans' private visits to the North are continuing as scheduled.

The spokesman for the North's Korean People's Army warned Sunday that its "revolutionary armed forces are compelled to take an all-out confrontational posture," citing Seoul's alleged policy of confrontation.

Unification Ministry spokesman Kim Ho-nyoun told reporters Monday that the government will calmly tackle the situation, taking various possibilities into account.

The North Korean military issued a similar threat in late 1998 ahead of its negotiations with the United States over Washington's demand for inspections of an alleged underground nuclear facility at Geumchang-ri in North Pyeongan Province.

At the time, the United States was also reportedly drawing up an emergency military plan, known as Operation Plan 5027 (OPLAN 5027), in preparation for contingencies in the North.

The ministry spokesman said that North Korea's threat issued in December 1998 was aimed at bolstering internal unity amid economic difficulties in the middle of winter as well as raising the morale of its military.