Ten more bodies found

The bodies were recovered from around and inside the stricken ferry, which has been largely off-limits during the rescue operation.

Divers were able to gain access to the ship for the first time on Saturday, when they initially found three bodies. Search teams had previously been unable to enter due to severe weather conditions.

More than 250 people are still missing four days after the ferry capsized en route from the South Korean mainland to Jindo island.

Most of the ferry's 476 passengers were school students and teachers on a class trip.

Just 174 people were pulled alive from the wreckage in the immediate aftermath of the accident.

Relatives are clinging to hope their loved ones may still be alive inside the ship in pockets of air, however, no survivors have been found since Wednesday.

Nearly 200 relatives of missing passengers started a march from Jindo on Sunday, saying they were heading for the presidential Blue House in Seoul, 260 miles (420km) to the north. But a large force of police officers blocked a bridge from the island to the mainland, making them turn back.

The captain of the vessel Lee Joon-seok has been arrested on five charges, including negligence of duty and violation of maritime law. Two of his crew members have also been detained.

They have been criticized for being among the first to leave the sinking ship.

It has also been revealed that Lee was not in charge of the vessel at the time of the accident and had handed the helm to a more junior third officer.

Acoording to local shipping crew this is standard practice, however, on the 13.5-hour journey.

Captain defends evacuation delay

The ship's crew are also being questioned over reports that some passengers were instructed to remain on the vessel for up to 40 minutes as it was sinking. Relatives suggest their loved ones may otherwise have had time to reach evacuation points.

Lee told reporters on Saturday that the delay in the evacuation order had been intended to save lives.

He said: "At the time a rescue ship had not arrived. There were also no fishing boats around for rescues, or other ships to help."

"The currents were very strong and the water was cold at that time in the area."

"I thought that passengers would be swept away and fall into trouble if they evacuated thoughtlessly," he added.

He reiterated his apology to the relatives of those on board the stricken vessel.

Investigations are underway into what caused the ferry to list sharply before sinking, although few explanations have yet been offered.

ccp/crh (AFP, AP, Reuters)