(CNN) -- Rescuers scanning the waters off the east coast of Papua New Guinea after a ferry sank found four bodies, authorities said Saturday.
Capt. Nurur Rahman, rescue coordinator for the National Maritime Safety Authority, said the bodies were recovered since rescue operations resumed earlier Saturday.
Some 246 survivors have been rescued in the aftermath of the sinking of the passenger ferry.
Nine aircraft were being used in the search for the more than 100 people who remained unaccounted for.
About 350 people were aboard the MV Rabaul Queen when it sank, Rahman said.
The Rabaul Queen went down about 16 kilometers (10 miles) off Cape Fortification in the Vitiaz Strait after getting into trouble early Thursday, officials said. It was ferrying passengers from the town of Kimbe on New Britain Island to Lae when it got into difficulty.
"Taking ferries is the most economic method of transport for people traveling between the islands and the mainland," Rahman told CNN Friday. "What I understand from local media is that a lot of students and their parents were traveling to schools that recently reopened on the mainland."
Jurgen Ruh, the chief executive of Manolos Aviation Ltd. in Lae, was in one of the helicopters that helped with the rescue effort.
He said he saw about 10 life rafts, each carrying roughly 10 people, the first time his helicopter flew overhead, he said. But, when the helicopter returned to the area after refueling, no more survivors were spotted.
It is likely the weather was a contributing factor in the ferry's sinking, Ruh said, as there were high winds at the time in what is a notoriously dangerous area.
Papua New Guinea had a population of 6.7 million in 2010, the U.S. State Department says, with about 190,000 people living in Lae. Most of the population is scattered in small settlements across the state's many islands.
CNN's Kim Chakanetsa, Elizabeth Joseph, Karen Smith and Jethro Mullen contributed to this report.