JINDO, South Korea, April 21 -- Death toll in a South Korean ferry sinking accident rose to 64 on Monday as divers kept entering inside the hull of the submerged vessel while ships were scouring the waters.

The sixth day into search and rescue operations, 64 people, 37 male and 27 female, have been confirmed dead as of 10 a.m. local time, 238 others are still missing. The number of the rescued remained unchanged at 174. "Search will pick up speed given favorable weather conditions and guideline ropes," Koh Myung-seok, spokesman of the pan- government response center, said at a press briefing.

Five guideline ropes were installed Sunday to guide divers against rapid currents to the gates of the sunken ferry, enabling divers to enter the hull at a faster pace than before. Two ropes were installed on the bow side, two on the stern side and one in the middle of the ship.

Divers entered inside the hull along their respective guideline ropes simultaneously, resulting in random discovery and retrieval of bodies trapped inside the ship.

Divers have already searched many cabins, which will be excluded from next search destinations, and it will also speed up their operations, Koh said.

The rescue efforts will be aided by favorable weather conditions such as calm waves and light wind. Waves are forecast to be 0.5-1 meter high in the area, with the wind to blow at a speed of 6-9 m/s. Water temperature is around 12 degrees Celsius.

Tidal currents are forecast to slow down from Monday to Thursday in waters off Jindo Island where the 6,825-ton ferry Sewol capsized and sank on Wednesday morning. The area is famous for swift currents which had hampered rescue operations.

The ferry departed South Korea's western port city of Incheon Tuesday night for the southern resort island of Jeju, carrying 476 people that included 325 high school students and 15 teachers on their way for a four-day field trip.

Hundreds of coast guard, navy and private divers will intensively search inside the hull Monday, while 213 rescue ships and 35 airplanes will scour the area near the submerged vessel, the spokesman said.

There are passenger cabins on the third and fourth floors of the five-story vessel and cargo compartments on the first and second floors, Koh said, adding intensive search will be conducted on the third and fourth floors.

Unmanned submersibles called remotely-operated vehicle (ROV) will be used to hunt outside the sunken vessel for bodies or possible survivors inside the hull.

However, the efficiency of the remotely-controlled submersible will not be high due to rapid currents in the waters, Koh said.

For overnight search operations, 214 ships and 35 airplanes were mobilized, while 151 military, police and private divers conducted underwater search 30 times.

Jigging fishing boats, which catch squids, worked at the scene overnight to offer lighting for nighttime search and rescue operations.

At 5:51 a.m., some divers cleared passages to a dining room on the third and fourth floors of the vessel, where many bodies or possible survivors are believed to be swarmed. Divers will try to enter the dining room at noon.

President Park Geun-hye on Sunday declared Jindo and Ansan as special disaster zones to facilitate the provision of necessary aid to the victims. Most victims came from the Danwon High School in Ansan, a Seoul suburb.

The process of delivering bodies to the bereaved families will be simplified, and necessary budgets will be spent to assist the heart-broken families. Joint mortuaries and memorial altars will also be launched.

First funerals for four Danwon High School students, who had been killed in the ferry sinking disaster, were held Sunday. The Sewol ferry capsized and sank off Jindo Island near the southwestern tip of the Korean Peninsula on Wednesday morning.