North, South Korea address U.N. over ship sinking

* Seoul officials give two-hour closed-door briefing

* North Korean ambassador to hold news conference Tuesday

By Louis Charbonneau

UNITED NATIONS (Reuters) - South and North Korea addressed the U.N. Security Council separately on Monday over the deadly sinking of a South Korean naval ship in March that has raised tension on the Korean peninsula.

Seoul, which has accused North Korea of torpedoing the corvette Cheonan on March 26, killing 46 sailors, brought the dispute to the Security Council this month, asking the 15-nation body to take action to deter "further provocation."

North Korea, which denies responsibility and accuses the South of fabricating the attack, asked Mexico's Claude Heller, the Security Council's rotating president, for a separate briefing session and the request was granted, a spokesman for the Mexican U.N. mission said.

Other council diplomats said the two informal back-to-back sessions would allow members to hear both sides of the story and to ask the South Korean delegation detailed questions about the investigation.

Diplomats said the council was unlikely to make any decisions on the basis of the briefings. They said the South Koreans and other individual council members might brief reporters afterward.

South Korea went in first. Civilian and military officials made a detailed technical Powerpoint presentation to the closed-door meeting followed by a question-and-answer session, diplomats who attended the two-hour meeting said.

"We presented and explained to the U.N. Security Council the evidence that the Cheonan was sunk by a torpedo which was made in North Korea and the launching was also done by a midget North Korean submarine," the co-head of the investigation, South Korean physics professor Yoon Duk-yong, told reporters.

Before his country's briefing, a senior North Korean envoy told reporters that Pyongyang rejected the South's case.

"We have nothing to do with that. We have nothing to do at all. We are just a victim. So we would like to make our position clear here," said Deputy Ambassador Pak Tok-hun. He said Ambassador Sin Son-ho would provide more details at a rare news conference at the United Nations on Tuesday.

MILITARY LEADERSHIP CHANGE

Mounting antagonism between the Koreas has worried investors, concerned about armed conflict breaking out, and set off a diplomatic scramble on all sides to cool tension.

Many analysts say neither side is ready to fight, despite frequent threats of all-out war from the North, but see the possibility of more skirmishes in a disputed sea border area off the west coast or along their heavily armed land border.

South Korea accused the North of violating the spirit of a landmark joint declaration struck by then South Korean President Kim Dae-jung and North Korean leader Kim Jong-il 10 years ago pledging peace.

That summit in Pyongyang led to warming ties between the rivals, including a growing trade relationship that has since been put on ice.

South Korean President Lee Myung-bak cut aid to the North when he took office in 2008, demanding Pyongyang drop its nuclear ambitions. That move angered its destitute neighbour.

The South's Unification Ministry spokesman, Chun Hae-sung, said the North must admit its role in the naval attack and apologise if it wants to see the ties reinstated. Pyongyang says the accusations are part of a U.S.-led plot.

A team of international investigators, led by South Korea's military, said in May that a North Korean submarine torpedoed the ship, presenting evidence that included parts of the weapon recovered from the site of the incident.

In the first in what some believe will be a string of high ranking military officers to be replaced over the ship sinking, South Korea's chairman of the Joint Chiefs of Staff was replaced on Monday for a perceived slow response.

South Korea's liberal opposition has been calling for the dismissal of the defence minister and other senior military officials, but so far Lee has resisted.

North Korea repeated its threat to blow up loudspeakers South Korea has set up at the border to broadcast anti-Pyongyang propaganda, keeping tension on the peninsula at its highest in years.

(Additional reporting by Jack Kim in Seoul; editing by Mohammad Zargham)