The South Korean military began lifting the stern of a naval ship that sank after an unexplained explosion near a contested sea border with North Korea.
The ship's stern is thought to hold the bodies of most of the 44 sailors who went missing after the ship sank.
Two bodies of 46 missing sailors were found before the lifting operation.
South Korea's defense minister said this month that the 12 hundred-ton Cheonan may have been hit by a torpedo, immediately putting suspicion on North Korea.
The salvage operation comes as tensions on the troubled peninsula have been ramping up.
North Korea has frozen the assets of a South Korean firm at a joint tourism project north of the border, once hailed as a symbol of cooperation.
One expert says South Korea would not likely take an aggressive stance if the ship were indeed torpedoed, because it could escalate into a major conflict that would harm the South's interests.
The ship sinking could also complicate the resumption of stalled international talks on ending North Korea's atomic arms program in return for aid to prop up its broken economy.