Park said it was increasingly clear that Captain Lee Joon-Seok had unnecessarily delayed the evacuation of passengers as the ferry started to sink, and then “deserted them” by escaping first.

Lee was arrested on Saturday along with a helmsman and the ship’s relatively inexperienced third officer, who was in charge of the bridge when the ship first ran into trouble.

“This is utterly unimaginable, legally and ethically,” she said, adding  that all parties to the disaster, from the owners to the safety inspectors to the crew, would be investigated and all those responsible would be held  ”criminally accountable.”

Her words came as a South Korean prosecutor confirmed that four more crewmembers had been detained on allegations of failing to protect passengers.

Senior prosecutor Ahn Sang-don told reporters that two first mates, one second mate and a chief engineer are also accused of abandoning the ship.

Ahn said prosecutors were considering whether to ask a court for a formal arrest warrant that would allow for a longer period of investigation. South Koreans can only be detained for 48 hours without a court-issued formal arrest warrant.

Grieving relatives were split yesterday over whether to approve an end to the search for survivors and let cranes raise the vessel to the surface.

There are five giant floating cranes at the scene ready to lift the vessel, but the president assured families of the missing that salvage operations would only begin after all hope of finding survivors was extinguished.

More than 60 people have been confirmed dead, but more than 240 are still unaccounted for - most of them children.

A psychological turning point came when divers began retrieving bodies from inside the ferry yesterday.

Watch: Captain of capsized South Korean ferry promised 'safe journey' in 2010 video

Many relatives had hoped passengers might have survived in trapped air pockets, and feared that raising the ship would have fatal consequences.

While some remain convinced their loved ones may be alive, others have begun to accept the probability there will be no survivors.

"I think the time may have come to use the large cranes," said the father of one student. "It's the practical option now, to prevent bodies being swept away by the currents and lost for good, or becoming too decomposed," said the man, whose son was one of 352 students from Danwon High School, near Seoul, on the ship.

He is among hundreds of distraught parents who have been staying at a gymnasium on the southern island of Jindo.

Officials remain extremely wary of formally calling off the rescue part of the operation, for fear of further upsetting relatives already incensed by what they saw as the slow and inefficient response to the ferry sinking. When some relatives spoke during a meeting about bringing in the cranes, others shouted them down.

"It's outrageous! What if even a single person remains alive in the ship?" asked Chung Hye-sook, the mother of a missing student. "Divers must go in and bring them out," Chung said.

Yesterday, almost 200 relatives set off on what they said was a protest march from Jindo to the presidential Blue House in Seoul - some 420 kilometres to the north.

They were later turned back by police after minor scuffles.