SEOUL - Bad weather, murky water and strong currents are hampering the search for survivors of the South Korean ferry disaster.
Emergency services are still searching for 287 people missing after a ship carrying 475 people sank.
Officials say 179 people have been rescued. Most of the passengers were pupils at the same high school.
South Korea's president visited the wreck and urged rescuers to "hurry".
Park Geun-hye said that time was running out and that every minute and every second was critical.
Nine people are confirmed to have died, with dozens more injured.
South Korea's Yonhap news agency has reported that one Russian and two Chinese are also among the missing
Military divers have been fighting high wind and waves to try to access the vessel but were not able to get into any of the cabins, the Chief of the West Regional Headquarters of the South Korean Coastguard Kim Soo-hyun said.
The emergency services are battling terrible weather conditions. Specialist divers and equipment are at the scene and that is now the focus of rescue efforts, but the conditions are extremely difficult. Divers say it has been impossible to get far enough inside the ship because the currents have been too strong, and those same currents have been whipping up mud and reducing visibility to almost zero. And as the minutes tick away, so do the hopes of finding any more survivors
He denied reports that three divers had been swept away and had to be rescued themselves, however.
Speaking at a news conference on nearby Jindo Island, Mr Kim said he would approve civilian divers who wished to join the search, provided there was "trust" between them and the official search teams.
He also expressed hope that the arrival of underwater cameras would help divers operating in waters with extremely low visibility.
Overnight, naval and coastguard vessels used floodlights and flares, to maintain a search now involving more than 500 divers, 171 vessels and 29 aircraft.
But distraught relatives gathered in a gymnasium on nearby Jindo island insisted more should be done, and vented their grief and frustration to anyone who would listen.
"Get my child out of that ship! Dead or alive," one distraught father repeatedly shouted to rescue and local government officials."