South Korean maritime police on Friday requested the pretrial detention of the first officer and helmsman of a passenger ferry that ran aground near the southwestern Jeolla county of Sinan, saying both were distracted and failed to steer the vessel.

Investigators say the Queen Jenuvia 2 struck an uninhabited islet on Wednesday evening after the first officer, who was checking his phone, failed to make a scheduled course change.

The helmsman denied wrongdoing, claiming he was watching navigation instruments. Recordings show the first officer ordering a rudder adjustment seconds before impact, but the helmsman said the forward lookout was the first officer's duty.

Police also plan to charge the captain with leaving the bridge in a narrow channel, in violation of the Seafarers Act, which requires direct oversight when navigating such waterways.

Authorities are analyzing phone data, questioning seven other crew members and investigating whether traffic control officers could have intervened.

The grounding injured 30 passengers but caused no life-threatening harm to the 267 people on board.