North Korean leaders continue to insist they had nothing to do with a March attack on a South Korean warship that left 46 sailors dead. They also promise to wage "all-out-war" if their country is punished for the incident.
South Korea, however, says its investigation overwhelmingly proves the North fired the torpedo that sank the vessel. It was South Korea's worst military disaster since the Korean War.
"(We) will take resolute countermeasures against North Korea and make it admit its wrongdoings through strong international cooperation," South Korean President Lee Myung-bak told Australian Prime Minister Kevin Rudd in a phone conversation, the presidential office said.
The White House called the attack an act of aggression that challenges international peace and security.
North Korea has remained steadfast in its denial, calling the investigation a "fabrication" and says it will react to any new sanctions with warfare.
"The all-out war to be undertaken by us will be a sacred war involving the whole nation, all the people and the whole state," a spokesman for North Korea's powerful National Defense Commission said, according to a report carried by the state-run Korean Central News Agency.