SEOUL - Sunken South Korean passenger ferry Sewol was raised to the surface on Thursday after having lain on the seabed for almost three years.

The vessel capsized and sank off Jindo Island, South Jeolla province on April 16, 2014, claiming the lives of 304 people, mostly high school students on a trip to the southern resort island of Jeju. Nine bodies were still unaccounted for.

Fifty divers and up to 400 other workers were involved in the operation, many from a consortium led by China's state-run Shanghai Salvage Co.

The operation started late Wednesday and should be completed on Friday providing sea conditions remain favorable. The waters off the Jindo Island are infamous for strong currents throughout the year.

Divers had installed beams underneath the wreckage to link the beams to jacking wires. Two barges then lifted the vessel, which had lain about 40 meters under the water.

If the ship is floated the targeted 13 meters above the surface, it will be moved to a semi-submersible barge that will carry the passenger ferry to a port in Mokpo, some 90 kilometers from Jindo Island.

Shanghai Salvage used a so-called "tandem lifting" system to lower the ferry to the ground. If successful, the Chinese company would become the world's first operator to lift a sunken ship using the method.

The company selected the method to raise the ship using beams and wires, instead of raising it with a crane or dismantling and lifting it.

Several relatives watched the much-anticipated operation unfolding from a boat near the site.

"To see the Sewol again, I can't describe how I'm feeling right now," said Huh Hong-hwan, whose 16-year-old daughter was killed in the accident. Her body has not been found.

Huh and his wife have for years maintained a bitter, defiant vigil in Jindo along with a handful of other relatives of missing victims.

"It took so long," Huh said.

Another parent, Lee Keun-hui, tearfully called for public support and prayers to help move the ship onshore intact and a full inquiry into the sinking "so a tragedy like this would never ever happen again".

"It breaks my heart to see the ship coming up," she said. "My daughter has been trapped in such a dirty, dark place for all these years."

The disaster was a crippling blow to the now-ousted leader Park Geun-hye, whose dismissal over a corruption scandal was confirmed by Seoul's top court only two weeks ago.

She stayed at her residence for the first few critical hours after the disaster while officials were frantically sending updates and asking for guidance.

She has never specified what she was doing for the seven hours, sparking wild rumors including a tryst and cosmetic surgery.