Aryanews- South Korea on Monday announced steps to tighten the vice on the North's already stumbling economy in punishment for sinking one of its navy ships, with both sides intensifying war-like rhetoric.
South Korean President Lee Myung-bak, in a nationally televised address, also said he would take the issue to the U.N. Security Council, whose past sanctions are already sapping what little energy North Korea's economy has left.
U.N. Secretary General Ban Ki-moon expressed confidence the Council would take "appropriate" measures.
The United States, which backs Seoul, said that the situation was "highly precarious". China, the North's only major ally, urged calm.
The mounting tension follows last week's report by international investigators accusing the North of torpedoing the Cheonan corvette in March, killing 46 sailors in one of the deadliest clashes between the two since the 1950-53 Korean War.
The United States, which has 28,000 troops on the peninsula, threw its full support behind South Korea and said it was working hard to stop the situation from worsening.
With U.S. Secretary of State Hillary Clinton in Beijing, Washington pressed China to rein in the hermit state.
China has avoided taking sides in the issue. Analysts say it is fearful of destablising the grip of North Korean leader Kim Jong-il, who is looking increasingly frail as he tries to secure the position of his youngest son as successor to the family dynasty that has ruled the state for more than 60 years.
The vitriolic comments across the heavily defended border are rattling investors and niggling at diplomatic relations.
Few analysts believe either Korea would dare go to war. The North's military is no match for the technically superior South Korean and U.S. forces. And for the South, conflict would put investors to flight.
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"I solemnly urge the authorities of North Korea ... to apologise immediately to the Republic of Korea (South Korea) and the international community," the South Korean president said in his address.
