Divers in the Philippines are making scant progress in their efforts to recover survivors — or bodies — from the scene where a ferry sank after colliding with a cargo ship near the central port city of Cebu.

About 35 people have been confirmed dead from MV Thomas Aquinas, which was carrying more than 800 passengers when it was struck late Friday and then sank within minutes.

Authorities says 750 people were rescued in the hours after the collision, but that more than 80 are still missing and presumed trapped inside the ferry as it went down.

Earlier, officials said 170 remained missing, but the number was reduced after a tallying error was discovered.

Philippine Navy spokesman Lt. Cdr. Gregory Fabic was quoted by AFP as saying rough seas hampered what he still described as a rescue effort.

"It is possible that there are air pockets in its compartments and there might be survivors," Fabic said. "There is still hope that there might just be survivors there."

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