Play Video North Korea Video: North Korea tears up agreements BBC Play Video North Korea Video: Obama blamed for Korean split Reuters Play Video North Korea Video: North Korea cuts ties with South Reuters SEOUL, South Korea â North Korea warned Sunday that South Korea's confrontational policies may trigger a war on the divided peninsula, a message coming two days after the communist country vowed to abandon all peace agreements with its southern neighbor. Relations between the two Koreas have been strained since conservative President Lee Myung-bak took office nearly a year ago in Seoul, pledging to take a harder line on the North. Tension heightened Friday when the North said it was ditching a nonaggression pact and all other peace accords with South Korea. The tension may lead to "an unavoidable military conflict and a war," North Korea's main Rodong Sinmun newspaper said in a commentary carried Sunday by the country's official Korean Central News Agency. "The policy of confrontation" by the South Korean government is "the very source of military conflicts and war" between the Koreas, it said. The North has accused Lee's government of preparing to stage a war, which South Korea denies. Earlier this month, the North's military declared it adopted an "all-out confrontational posture" to defeat any southern aggression. In its Friday statement, the North said it would no longer respect a disputed sea border with the South on the west of the peninsula, raising the prospect for a new armed clash in the area â already the scene of bloody naval skirmishes in 1999 and 2002. President Lee sought to downplay the statement and called it "not unusual." He indicated his government will wait until the North is ready for talks in good faith. A South Korean Defense Ministry official said Sunday that the country's navy remains on alert along the western sea border. The official â speaking on condition of anonymity citing department policy â said the ministry has not detected any unusual movements of the North Korean military. The two Koreas technically remain at war because their three-year conflict ended in 1953 with a truce, not a peace treaty. The peninsula remains divided by a heavily fortified border, with tens of thousands of troops stationed on both sides.