Investigators: North Korea fired torpedo that sank ship

SEOUL, South Korea -- Evidence overwhelmingly proves North Korea fired a torpedo that sank a South Korean warship in March, killing 46 sailors, investigators said Thursday.

South Korean President Lee Myung-bak vowed "stern action" for the provocation and called an emergency security meeting for Friday, the presidential Blue House said.

The long-awaited investigation results from a multinational team said a torpedo caused a massive underwater explosion that tore the Cheonan apart on March 26.

Fifty-eight sailors were rescued from the frigid Yellow Sea waters near the Koreas' maritime border, but 46 perished -- South Korea's worst military disaster since the end of the three-year Korean War in 1953.

Fragments recovered from the waters near the Koreas' maritime border indicate the torpedo came from communist North Korea, investigators said.

"The evidence points overwhelmingly to the conclusion that the torpedo was fired by a North Korean submarine. There is no other plausible explanation," the South Korean-led investigation team said.

The civilian and military investigation team included experts from South Korea, the U.S., Australia, Britain and Sweden.

North Korea has denied involvement in the sinking of the 1,200-ton warship. Vice parliamentary speaker Yang Hyong Sop earlier this week criticized Seoul for "unreasonably" linking his country to the incident, according to the North's state radio station.

The report's release is likely to further increase tensions on the divided Korean peninsula, where the 1950-53 Korean War ended in a truce, rather than a peace treaty. The land border is the world's most heavily armed, and the western sea border has been the site of several deadly naval clashes since 1999.

North Korea disputes the maritime border drawn by the United Nations at the close of the war in 1953.