THE South Korean President, Lee Myung-bak, has called for ''resolute counteractions against North Korea'' as the North yesterday labelled a report finding it torpedoed a South Korean warship a ''fabrication''.
North Korea threatened ''full-scale war'' if the international community tightens sanctions in retaliation. However analysts said that although the Korean peninsula had been rocked by the March 26 attack, bellicose language was typical of the North.
The South Korean military presented the findings of a multinational investigation into the sinking of the Cheonan, which killed 46 sailors, yesterday alongside senior Australian and US naval officers who endorsed the findings.
As world powers lined up to condemn North Korea for breaching a 1953 armistice agreement, diplomats emphasised the scientific nature of the evidence uncovered by an investigating team that included 24 Australian, US, British, Canadian and Swedish defence experts.
The Prime Minister, Kevin Rudd, said the report findings were ''deeply disturbing''.
''The international community cannot let this act pass without an appropriate response,'' Mr Rudd said.
The government would work with South Korea on a response that included action in the United Nations Security Council, he said.
The international security program director at the Lowy Institute, Rory Medcalf, said: ''The big challenge is not so much getting new sanctions but getting China to implement existing sanctions. In the past 18 months it has been clear China has been tightening its relationship with North Korea rather than pushing it away.''
Yesterday's findings ''will make it harder for China to maintain that position'', Mr Medcalf said.
The US Secretary of State, Hillary Clinton, is due to visit Beijing and Seoul next week and is expected to seek China's backing for a tough Security Council resolution. The report found ''there is no other plausible explanation'' than the Cheonan sank after a torpedo was fired by a North Korean submarine.
A homing torpedo exploded below the gas turbine room and split the ship apart, the investigators said.
The central evidence linking the attack to North Korea was a torpedo propeller and steering parts recovered from the wreck that matched drawings of a torpedo presented by North Korea in marketing brochures to foreign countries for export sales.
The Korean marking for ''1'' on the propeller was also identical to that on a North Korean torpedo previously obtained by South Korea.
''The weapon system used is confirmed to be a high-explosive torpedo ... manufactured by North Korea,'' said the report.
Australian navy Commander Anthony Powell, among five Australian defence investigators involved, was in South Korea at the presentation of the report.
North Korea's National Defence Commission denied it was responsible for the sinking and said it would send its own inspectors to South Korea.