North Korean leader Kim Jong Il said his country must bolster its armed forces, state media reported Sunday, two days after his regime warned it would launch a war against South Korea if necessary.

Kim's all-powerful National Defense Commission had threatened Friday to initiate a sacred "retaliatory battle" against the South in anger over its reported contingency plan to cope with potential unrest in the communist country. The commission also warned it could break off all dialogue and negotiations with the South.

On Sunday, the North's official Korean Central News Agency said Kim had inspected a joint army, navy and air force drill that demonstrated the country's "merciless striking power" against anyone trying to infringe on its territory.

Kim expressed his satisfaction with the drill and assigned the military tasks to develop it into "the invincible revolutionary armed forces," according to the KCNA report.

The report did not say when or where the joint drill took place.

Kim routinely visits military units and inspects their training to bolster his "songun," or "military-first," policy that rewards the 1.2 million-member armed forces — the backbone of his authoritarian rule of the country's 24 million people. He often calls for a stronger military during the visits.

The report of his latest inspection, however, came two days after his defense commission issued a rare statement strongly protesting the South's alleged contingency plan, which it says is aimed at toppling Kim's regime.

The commission said "a sacred nationwide retaliatory battle to blow up the stronghold of the South Korean authorities," including the presidential office, would begin once the plan was completed and put into practice. It also said the country would push for Seoul's expulsion in any negotiations on peace on the Korean peninsula if the South didn't apologize for the plan.

The warning came as a surprise since the North recently offered conciliatory gestures to the South, including a proposal Thursday to discuss resuming stalled joint tour programs.

Seoul expressed regret over the North's threat, which it said was driven by unconfirmed media reports.

South Korea has reportedly drawn up a military operations plan with the United States to cope with possible emergencies in North Korea. South Korea's Defense Ministry has consistently declined to comment about the existence of such a plan.

North Korea occasionally issues statements that include threats to destroy South Korea. Authorities in Seoul monitor them carefully but usually take them in stride.

South Korea's Defense Ministry said the North had held annual winter military training but had no information on Kim's latest military inspection. A ministry official said there had been no suspicious activities by the North's military in recent days.

Another South Korean government official downplayed the significance of the North's latest joint drill, saying it appeared to be part of routine training. The official said it was the first time the North's media had reported Kim's inspection of a joint drill of the three armed services.

Both officials spoke on condition of anonymity, citing department policy.

The two Koreas remain technically at war because the 1950-53 Korean War ended in a truce, not a peace treaty.