South Korean prosecutors on Monday demanded the death penalty for the captain of a ferry that sank in April, killing more than 300 people, and life sentences to three key crew members, news reports said.

Prosecutors also requested that a district court sentence 11 other crew members up to 30 years in prison on charges that they were negligent and failed to protect passengers when the ferry was sinking April 16, South Korean media reported. Most of those who died in the disaster were high school students on a school trip.

Capt. Lee Joon-seok and three other crew members from the ferry Sewol were indicted on homicide charges, alleging they were negligent and failed to protect passengers when the ferry sank. Eleven other crew members were indicted on less serious charges. The 15 crew on trial were among the first group of people to leave when the ship began badly listing.

The Gwangju District Court said it couldn't immediately confirm the news reports.

The sinking, one of South Korea's deadliest disasters in decades, caused nationwide grief and fury, with authorities blaming overloading of cargo, improper storage, untimely rescue efforts and other negligence for the incident. More than six months after the sinking, the bodies of 294 people have been retrieved, while 10 others have not been found.

Lee has apologized for abandoning passengers, but says he didn't know his action would lead to the mass deaths. In a video taken by the coast guard on the day of the sinking, he was seen escaping the ferry in his underwear to a rescue boat while many passengers were still on the sinking ship.

Many student survivors have said they were repeatedly ordered over a loudspeaker to stay on the sinking ship and that they didn't remember any evacuation order being given before they helped each other flee the vessel.

Lee has said he issued an evacuation order for passengers. But he initially told reporters days after his arrest that he withheld the evacuation order because rescuers had yet to arrive and he feared for the passengers' safety in the cold, swift waters.