Cambodian Prime Minister Hun Sen on Friday extended his deepest sympathy to the victims and members of the bereaved families in a ferry sinking incident off South Korean coast on Wednesday.

"I am extremely saddened to learn about the loss of lives and more than two hundreds of people unaccounted-for caused by the sunken ferry in the southern coast of the Republic of Korea on Wednesday," the premier said in a condolence message to South Korean President Park Geun-hye.

"On behalf of the Royal Government, people of Cambodia and in my own name, I'd like to convey to Your Excellency, to the Government and the people of the Republic of Korea, particularly to the victims and members of the bereaved families, our deepest sympathy and profound condolences for this unfortunate tragic accident," he said.

The ferry carrying 475 people, mostly high school students, capsized off South Korea's coast on Wednesday. So far, 28 people were confirmed dead and 268 others are still missing.

Three large salvage ships arrived at the scene Friday morning to pull the ship out of the waters, and another one got there in the evening. It was expected to take over one month to salvage the submerged vessel.

A total of 535 coast guard and navy divers were working at the scene, and 31 airplanes and 173 rescue ships were deployed for search and rescue operations.