President Lee Myung-Bak will Monday outline South Korea's response to the sinking of a warship that Seoul said was torpedoed by a North Korean submarine, claiming 46 lives, his spokesman said.

The attack on the Cheonan near the disputed border with the North on March 26 sparked outrage and grief in South Korea, but Seoul has apparently ruled out any military counterstrike for fear of triggering full-scale war.

As international anger grows over the attack, Lee, in an address to the nation, will also outline his planned appeal to the UN Security Council over the sinking of the corvette.

"The president will announce... measures, some for us to take and also others to be taken through international cooperation," senior presidential spokesman Lee Dong-Kwan said in a statement Sunday.

"He will also mention a plan to bring the case to the UN Security Council," the spokesman said, adding that President Lee would ask the Council to impose further sanctions on his country's neighbour.

The statement follows remarks made by South Korean officials, who said Seoul would seek sanctions against North Korea after an international inquiry found "overwhelming" evidence it had attacked the Cheonan.

The North has repeatedly denied the allegation after Seoul Thursday released the investigators' report, which found that the 1,200-tonne corvette had been destroyed by a torpedo.

In an unusually swift response, the North's powerful NDC (National Defence Commission), chaired by leader Kim Jong-Il, said the report was based on "sheer fabrication."

The incident has been condemned by the international community but Seoul is said to have ruled out any military retribution.

Instead, Seoul has been engaged in hectic diplomacy to win support for its bid to refer Pyongyang to the UN Security Council for punishment.

"This incident is so serious and grave an issue that we must be very cautious and prudent in handling it," President Lee told his National Security Council last week.

South Korean Defence Minister Kim Tae-Young said Seoul would seek sanctions against North Korea, in addition to those already imposed for its missile and nuclear tests.

US Secretary of State Hillary Clinton, on a visit to China, has briefed her Chinese counterpart Dai Bingguo on the inquiry into the sinking, a senior US official said Sunday.

"We've shared with them some specific information" during a dinner ahead of US-China dialogue due to start in Beijing on Monday, the official said on condition of anonymity.

Clinton also told Dai the substance of a statement due to be made by Lee, and said Washington would back all measures announced.

On Saturday the North made fresh demands that the South must receive Pyongyang's investigators and show them evidence that the North torpedoed the warship.

But the South's defence chief rejected the demand, saying it would be "like a robber or a murderer insisting he must inspect the crime scene."

Seoul has said it will let the US-led United Nations Command handle the case. The command, which supervises the armistice after the 1950-1953 Korean war, said it would launch its own inquiry to review the findings.

The two Koreas still remain technically at war since the conflict.

Seoul's National Intelligence Service (NIS) said Sunday it had raised a nationwide alert against possible hackings into government computer networks, by one notch from "normal" to "attention," in response to the Cheonan report.

"It is imperative to beef up security against cyber attacks like hackings into state computer networks, in relation to the results of investigating the sinking of the Cheonan," the NIS-run National Cyber Security Centre said.

Rodong Sinmun, the North's ruling communist party newspaper and official mouthpiece, said Sunday the South's probe results were a "premeditated plot to push the inter-Korean relations to total collapse and ignite a war."

earlier related report
US, S.Korea say they will make N.Korea pay for sinking
Seoul (AFP) May 22, 2010 - The United States and South Korea vowed Friday to make North Korea pay the price for torpedoing a warship in March, as international anger grew over the attack which claimed 46 lives.

In Tokyo, visiting US Secretary of State Hillary Clinton said it was "important to send a clear message to North Korea that provocative actions have consequences".

Seoul Defence Minister Kim Tae-Young, a day after investigators reported overwhelming evidence that a North Korean submarine sank the South Korean corvette, said: "North Korea surpassed the limits and for such an act we will make it pay."

At the start of an Asian tour that later Friday took her to Shanghai, ahead of planned stops in Beijing and Seoul, Clinton said she and Japan's Foreign Minister Katsuya Okada agreed the North must end its belligerence towards neighbours.

"We cannot allow this attack to go unanswered by the international community," she said, adding she looks forward to "intensive consultations in China".

The attack on the Cheonan near the disputed border with the North on March 26 sparked outrage and grief in South Korea, but Seoul has apparently ruled out any military counterstrike for fear of triggering full-scale war.

"This incident is so serious and grave an issue that we must be very cautious and prudent in handling it," said President Lee Myung-Bak after convening his first National Security Council meeting in almost a year.

Seoul is engaged in hectic diplomacy to win support for its bid to refer Pyongyang to the United Nations Security Council for punishment.

The communist North, for the second time in two days, denied involvement and accused Seoul of faking the evidence. It has threatened "all-out war" in response to any attempt to punish it.

China, the North's ally and a veto-wielding Security Council member, would have to support or abstain in any move to tighten sanctions further.

Unlike Western nations and Japan, Beijing has so far failed to condemn the North for the attack and merely called for restraint by all sides.

South Korea believes it has a strong case, after parts of a torpedo were salvaged last Saturday from the murky depths of the Yellow Sea.

Defence officials Friday again put the salvaged propellers and other items on display.

Experts pointed out similarities between the salvaged weaponry and a blueprint the North has used when exporting such torpedoes. They said explosive residue found on the weaponry matches that on the warship's hull.

A top intelligence official said the North apparently launched the attack partly in revenge for a naval firefight near the border in November which left one of its patrol boats in flames.

The aim was "to restore honour to the military and boost its morale", said the director of the Defence Intelligence Agency, Lt Gen Hwang Won-Dong.

Minister Kim said Seoul would seek additional Security Council sanctions among other measures.

Those measures are expected to be announced early next week by the president, who Friday termed the torpedo attack a breach of the armistice agreement that ended the 1950-53 war.

The North Friday reiterated that its neighbour was fabricating the case and said the situation on the peninsula is akin to war.

"It just produced fragments and pieces of aluminium whose origin remains unknown as 'evidence', becoming the target of derision," it said.

"The fabrication of the case (is) in the final analysis, nothing but a farce orchestrated by the group of traitors with the approval of the US and under its patronage.

"As the DPRK had already clarified, it has nothing to do with the case. The DPRK has always abided by international law."

Andrei Lankov, of South Korea's Kookmin University, said the sinking showed that the Pyongyang regime "is becoming less calculating, less rational and less Machiavellian than it used to be".

"And that is not good news," he wrote in the Korea Times, suggesting that leader Kim Jong-Il's apparent stroke in 2008 might be partly responsible.

The US-led United Nations Command said it would launch its own inquiry to review the findings of Seoul's investigation "and determine the scope of armistice violation that occurred in the sinking".

The command has been in the South since the UN sent an international force to defend it after the Korean War broke out in 1950.