South Korea announced Thursday that a torpedo fired from a small North Korean submarine caused the external underwater explosion that sank the South Korean 1,200-ton corvette Cheonan on March 26. It said no other explanation was plausible. Forty-six South Korean sailors died or went missing in the sinking. The announcement was based on an investigation by a team of experts from South Korea, the United States, Australia, Britain and Sweden.
North Korea called the investigation results a "conspiratorial farce." But the evidence is strong. Torpedo parts recovered at the explosion site on May 15 perfectly match the schematics of the CHT-02D 1.7-ton, 21-inch-diameter torpedo with a 250-kg explosive payload. The torpedo is included in the North's brochure for weapons exports, and the "No. 1" marking in the Korean alphabet on the propulsion section matches the marking on a previously obtained North Korean torpedo. The team said the torpedo exploded three meters away from the port side of the corvette's engine room and six to nine meters below the sea surface.
North Korea reacted by saying that if South Korea takes retaliatory action, it will "answer with all-out war." South Korea will bring the matter to the U.N. Security Council and scale down trade with and aid to the North. Sanctions against the North may be strengthened. The South's actions may dwindle the North's channel for obtaining foreign currencies. The nations concerned must strengthen cooperation to prevent the desperate North from trying to heighten military tension.