Lee leaves \"window of opportunity\" open for better ties

South Korean President Lee Myung-bak said Monday that South Korea has left a \"window of opportunity\" open to improve relations with North Korea as the North\'s new leader Kim Jong-un took over the communist state following the death of his father. In a nationally televised New Year\'s address, however, Lee said that Seoul will \"strongly respond\" to any provocative acts from Pyongyang, calling for his military to maintain a heightened vigilance against the North, South Korea\'s news agency (Yonhap) reported. \"The most important target at this moment is peace and stability on the Korean Peninsula,\" Lee said. \"We are leaving a window of opportunity open. \"If North Korea shows its attitude of sincerity, a new era on the Korean Peninsula can be opened,\" Lee said. Lee also expressed hope that this year will mark a \"turning point\" in resolving the North\'s nuclear standoff but repeated his previous stance that the six-party talks on ending North Korea\'s nuclear weapons programs can resume only if Pyongyang halts all of its nuclear activities. \"As long as the possibility of North Korea\'s provocation remains, we will maintain a watertight defense posture,\" Lee said. \"If provoked, we will strongly respond.\" On Sunday, North Korea issued its New Year\'s message urging its military and people to become \"human rifles and bombs\" to defend Kim Jong-un and rally behind the young leader. Inter-Korean ties are currently at one of their lowest levels in years. In its latest hostilities against South Korea in 2010, North Korea sank a South Korean warship and attacked a border island with artillery fire, killing a total of 50 South Koreans. Last year, diplomatic efforts to resume the six-party talks gained momentum, but the death of Kim left prospects for a resumption of the talks more uncertain. The multilateral talks, which involve the two Koreas, China, Japan, Russia and the US, have been dormantsince late 2008. Days before the reported December 17 death of Kim, North Korea and the US held talks in Beijing. Pyongyang had been poised to announce an agreement with Washington to suspend its uranium enrichment program and accept UN nuclear monitors in exchange for food aid. Such moves by North Korea were preconditions set by South Korea and the US for resuming the six-party talks.