South Korea has formally asked the UN Security Council to respond to the sinking of one of its warships allegedly by North Korea despite a threat of retaliation from its communist neighbour.
South Korea's UN Ambassador Park In-Kook told reporters he handed a letter to council chairman Mexican Ambassador Claude Heller requesting "action by the Security Council commensurate with the gravity of the situation".
The South Korean envoy gave no further details on the content of the letter.
But Heller, who is chairing the Security Council this month, told reporters he would start consultations with other council members "to give an appropriate reply". He did not say when.
A copy of the letter obtained by AFP in Seoul and translated from Korean noted the conclusions of a multinational investigation last month that a North Korean submarine torpedoed the South Korean warship Cheonan in March, killing 46 people on board.
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"As North Korea's armed attack poses a threat to international peace and security, we request the UN Security Council to discuss this matter and deal sternly with North Korea's military provocation," the letter said.
Seoul has announced a series of reprisals including cutting off trade with its Stalinist neighbour.
Pyongyang has denied any role in the sinking and has responded to the reprisals with threats of war, sending regional tensions spiking.
Earlier on Friday, South Korean President Lee Myung-Bak announced in Singapore that his government was referring the case to the Security Council.
"Today, the Republic of Korea government referred the matter of North Korea's attack against the Cheonan to the United Nations Security Council," Lee said in a speech to an annual security forum.
He mentioned no sanctions but called the March sinking of the corvette a "military provocation" and dismissed Pyongyang's denials of involvement as "laughable".
Tensions soar
Tensions have soared on the peninsula since the deadliest peace-time incident for Seoul since the end of the Korean War in 1953.
The South Korean foreign ministry argued North Korea's alleged torpedo raid breached chapter seven of the UN Charter, and part of chapter two on a truce accord which ended the 1950-53 Korean War.
It said Seoul's request was based on chapter 35 of the UN Charter that states that UN member states can draw the council's attention to any matters that can threaten international peace and security.
South Korean Vice Foreign Minister Chun Young-woo met with several council ambassadors on Wednesday and Thursday to lobby for Security Council action against North Korea.
South Korea can count on the full support from the United States, Japan and other Western powers but to secure adoption of the censure resolution, it must also enlist support from veto-wielding council members Russia and China which have traditionally been close to Pyongyang.
Russia, which has said it needs "100 per cent proof" of the North's involvement, on Monday sent a team of naval experts to South Korea to review findings of the multinational probe and visit the site of the sinking.
The South Koreans have also asked China to send its own experts but Beijing has not responded, according to media reports.
