A boy holds a candle during a candlelight vigil to wish for the safe return of missing passengers from the sunken South Korean ferry Sewol, at a park in Ansan April 20, 2014. [Photo/Agencies]

MOKPO, South Korea - A South Korean prosecutor says four more crew members from a sunken ferry have been detained on allegations of failing to protect passengers.

Passengers wait for words

'I am sorry,' captain says

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

Ahn says prosecutors are 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.

The ferry's captain and two other crewmembers were previously formally arrested on suspicion of negligence and abandoning people in need.

Sixty-four bodies have been recovered, and about 240 people are still missing.

S.Korean president says captain's deserting ferry amounts to "murder"

SEOUL - South Korean President Park Geun-hye strongly criticized the captain and some of his crew members of the ferry Sewol on Monday for leaving hundreds of passengers behind and deserting the sinking ship, saying what they did amounted to an act of "murder," local media reported.

Park also vowed to uncover all irregularities involved in the ferry's operations and force those responsible to take "criminal and civil" responsibilities regardless of their ranks.

At a meeting with senior aides, the president acknowledged there were serious problems with the government's initial response to the disaster that left more than 300 people dead or missing.

"Above all, the conduct of the captain and some crew members is unfathomable from the viewpoint of common sense, and it was like an act of murder that cannot and should not be tolerated," Park told senior secretaries, quoted by the Yonhap news agency.