Rescue efforts are under way to find the 46 South Korean sailors who remain missing after an explosion sank their naval ship on March 26.
South Korean authorities say 58 sailors were rescued following the accident, one of the South's worst sea disasters. But hopes are fading of finding more survivors in the near-freezing waters.
The 1,200-ton patrol ship sank near the disputed maritime border with North Korea after an unexplained explosion at the rear of the hull, sparking fears the vessel may have been attacked by the North.
The ship went down near the Yellow Sea border off the west coast of the peninsula, the scene of two deadly naval fights between the two Koreas in the past decade.
The two sides have been technically at war since their 1950-53 conflict ended only in a truce rather than a peace treaty.
Officials sought to play down suggestions North Korea was involved in the accident off Baengnyeong Island, which the South uses as a military outpost.
Presidential office spokesman Kim Eun-hye told a news briefing today in Seoul that there had been no unusual movements by North Korea.
She said President Lee Myung-bak had nonetheless told an emergency government meeting that all scenarios would be investigated. "President Lee emphasized every possibility should be considered in investigating the cause thoroughly and promptly," Kim said.
The military said it would issue an official statement on the cause of the accident after rescue teams raise the ship for analysis. Local media said this could take up to 20 days.
But some relatives of missing sailors appear unwilling to wait that long. About 150 distressed relatives today clashed with army officials at a naval base south of Seoul, accusing the military of concealing information about what caused the disaster.
Some claim rescued crew members told them the ship was leaky and in need of repair.
with agency reports