Newly-released video reveals the harrowing final moments of a group of teenagers on the ship as it capsized.
There is still no official explanation for the sinking, although the government has launched a formal inquiry.
Hundreds of South and North Koreans have been reunited for the first time in six decades after being separated by the Korean War.
The president of South Korea Park Geun-hye is to make a televised speech this week apologising to the families of the 286 victims killed in the Sewol ferry disaster, her office has said.
According to state news agency Yonhap, the South Korean president will make a public apology to the nation on Monday morning, a month after the disaster occurred.
She is due to reveal plans to overhaul the national security system and government bureaucracy, and revamp the emergency management system, officials told the news agency.
South Korean prosecutors indicted four crew members of a ferry that capsized in April killing more than 280 passengers for manslaughter, a senior prosecutor said today.
The prosecution also indicted all 11 other surviving crew members of the Sewol for negligence.
The crew has been under criminal investigations after they were believed to have escaped the sinking vessel before many of the passengers.
A civilian involved in the search for dozens of missing people from a South Korean ferry disaster has died, after falling unconscious during a dive. He later died in hospital, authorities said.
According to other task force team officials, the 53-year-old diver was pulled to the surface by fellow divers after losing communication spokesman Ko Myung-seok said.
A diver searching for bodies on board the sunken South Korean ferry Sewol has died, according to South Korean state media.
Diver dies during search for missing from sunken ferry http://t.co/qZIDRdtafY
Eleven more bodies were retrieved from the ferry that sunk off the coast of South Korean bringing the confirmed death toll to 259 and the number of those missing to 43, South Korean news agency Yonhap has reported.
Death toll from sunken ferry rises to 259 http://t.co/2Jwg1prAgM
The number of people injured in a collision between two underground trains in the South Korean capital has risen to 170, according to South Korean news channel YTN television. Earlier estimates had put the number of injured at 40.
Two underground trains collided at a station in the South Korean capital of Seoul injuring around 40 passengers, according to Reuters.
One carriage derailed due to the impact of the collision and passengers walked from the tracks to the station, South Korean news channel YTN television said.
North Korea's military has begun a firing drill near the South Korean border.
South Korean authorities said they had been notified by the North Koreans that the artillery drill would be taking place in two areas near populated islands.
South Korea's president has accepted her prime minister's resignation over the government's handling of a deadly ferry sinking.
Park Geun-hye did not set a last day in office for Prime Minister Chung Hong-won, who offered his resignation today and blamed "deep-rooted evils" in society for the tragedy, which has left more than 300 people dead or missing.