Navy ships and surveillance planes were searching for more survivors Saturday as a team of 18 navy divers has begun an underwater investigation into the cause of the sinking of the 1,200-tonne Cheonan off Baengnyeongdo, an island near the border with North Korea.
Reports say it was carrying French- and US-made anti-ship missiles as well as torpedoes and other weapons.
Joint Chiefs of Staff officer Lee Ki-Shik told journalists that the military was "very cautious about pointing fingers at North Korea or any other causes at the moment."
Officials said there were no abnormal military movements on the other side of the North/South Korean border at the time of the sinking.
"We are detecting no abnormal movement from North Korea," said a Joint Chiefs of Staff spokesperson Park Sung-Woo.