Diver dies at S. Korea ferry disaster site

The 53-year-old was on his first dive at the site and suffered breathing difficulties after reaching a depth of 25 metres (82 feet), coastguard spokesman Ko Myung-Suk told journalists.

The diver, who was identified only by his surname Lee, lost consciousness and was pronounced dead at a hospital, Ko added.

Full details of what happened have yet to emerge but Yonhap news agency reported he was a veteran crew member of private firm Undine Marine Industries, a specialist in maritime rescue work.

Lee was the first victim among scores of divers who have been engaged in the grim task of finding and retrieving bodies from the sunken ship in hazardous and challenging conditions such as fast currents and silty water.

Some 10 other divers have received treatment for exhaustion and decompression sickness since the operation began.

It has been 20 days since the 6,825-tonne Sewol capsized and sank with 476 people on board -- most of them schoolchildren -- off the southern coast.

President Park Geun-Hye on Tuesday issued a fresh apology for her government's failure to prevent the tragedy. The confirmed death toll stands at 263, while 39 people remain missing.

"As the president who should protect the lives of the people, I don't know how to express my condolences to the bereaved families. I feel sorry and my heart is heavy with grief", she said.

"Greed for material gains prevailed over safety regulations and such irresponsible behaviour resulted in the loss of precious lives", she added.

Park had apologised for her government's failure to combat systemic and regulatory "evils" that may have contributed to the accident and vowed to "sternly punish" any culprits.

The ferry sinking is one of South Korea's worst peacetime disasters, made all the more shocking by the loss of so many young lives.

Of those on board, 325 were students from the same high school in Ansan city, just south of Seoul.

All the 15 crew including the captain have been arrested for abandoning the ship while hundreds were trapped inside.

Prosecutors also arrested three officials from the ferry operator -- Chonghaejin Marine Co -- last week on charges of loading the ferry well beyond its legal limit.

Yonhap news agency, citing investigators, said Tuesday that the Sewol ferry was loaded with just 580 tonnes of ballast water -- only 37 percent of the legal requirement -- in order to carry more cargo. This made the ship dangerously imbalanced.

Investigators said on Monday that the crew had failed to alert passengers to the imminent danger for 40 minutes after the crew sent distress signals and became the first to leave the ship aboard a rescue boat, leaving hundreds of passengers trapped inside the sinking ship, according to Yonhap.

Criticism has also been directed at the government, as more evidence emerges of lax safety standards and possible corruption among state regulators.