Rescue workers retrieved 12more bodies from a sunken ferry late Tuesday in desperate search operations against rising tides and strong currents for nearly 100 passengers still missing.

The bodies were recovered from the sunken ferry Sewol on Tuesday afternoon, raising the death toll to 205 according to the Coast Guard. Still, 97passengers remain unaccounted for.

After recovering four bodies in their overnight job, Coast Guard, Navy and civilian divers have been struggling to re-enter the ill-fated ship that capsized on April 16 in waters off South Korea's southwestern island of Jindo.

"Our job will focus on searching the right side of the fourth floor of the boat ... as we've failed to gain access to the side because the ship was sunken with the right side touching the bottom," an official of the state response team said.

Of 476 passengers aboard, mostly high school students on a field trip, 174 people, including the captain and most of the crew, were rescued shortly after the accident, but no one has been found alive since.

Search efforts have been hampered by bad weather and strong underwater currents at this time of spring tides.

Spring tides refer to tides in which the difference between high and low tide is the greatest. Currents are stronger by about 40 percent during spring tides compared with a period of neap tides when the difference is the least.

The spring tides are expected to last until Friday, officials said. (Yonhap)