South Korean President Lee Myung-Bak has warned Pyongyang that any provocation against "an inch of our territory" would be met with a strong response.
"Any provocation that would pose a threat to our lives and property will not be tolerated. Such provocations will be met with stern, strong responses," the Associated Press quoted Lee as saying during a New Year address on Monday.
He, however, added that Seoul is still open to possible peace talks with its northern neighbor despite high tensions on the Korean Peninsula.
"The door for dialogue is still open," he said. "If the North exhibits sincerity, we have both the will and the plan to drastically enhance economic cooperation together with the international community."
Tensions have been high on the Korean Peninsula since a November 23 exchange of artillery fire which left four South Koreans, including two civilians, dead. The incident was of particular importance as it was the first shelling of a civilian area in the South since the 1950-53 Korean War.
The crisis further deepened over rounds of joint military drills South Korea held with the United States despite threats of retaliation from Pyongyang.
The South Koran president also called on the North to give up its "military adventurism."
"The North must come to the realization that nothing can be gained through military adventurism.... Nuclear weapons and military adventurism must be discarded," he went on to say.
Lee also vowed to boost his country's defense capability as "the situation before and after the provocation against Yeonpyeong Island cannot be the same."
The comment came as Stephen Bosworth, the US envoy for North Korea, is expected to visit the region to discuss how to defuse tension on the Korean Peninsula.
The US State Department said that Bosworth will visit Seoul on Tuesday and then visit China and Japan for "further consultations on the North."