Search teams have resumed efforts to find more than 80 people still missing after a ferry and a cargo ship collided in the Philippines.
At least 34 people died when the MV Thomas Aquinas sank off the central port of Cebu on Friday with more than 800 people onboard, officials said.
Poor weather has disrupted attempts to send down divers into the wreckage.
A navy spokesman said it was possible survivors could be found inside air pockets, although chances were slim.
The number of people officially listed as missing was reduced on Sunday from a previous figure of 170 due to tallying issues.
The authorities say more than 750 people have been rescued since the collision, which happened in calm waters around 2km (1.2 miles) from the shore.
Coastguard and military vessels helped with the search operation, but it has been hampered by rough seas.
Navy spokesman Lt Cdr Gregory Fabic told AFP the weather had prevented divers from reaching the interior of the sunken vessel, where many of those missing were believed trapped.
"It is possible that there are air pockets in its compartments and there might be survivors," he said.
"There is still hope that there might just be survivors there."
Philippines President Benigno Aquino has ordered an investigation into the collision.
BBC South East Asia correspondent Jonathan Head says this is likely to focus on whether the narrow lanes approaching Cebu harbour were used incorrectly.
Survivors said hundreds of passengers jumped into the ocean as the ferry began taking on water and listing on Friday evening. The crew distributed life jackets.
Many were asleep when the crash happened and others struggled to find their way in the dark, reports said.
One survivor, Jerwin Agudong, said he and other passengers jumped overboard in front of the cargo vessel.
"It seems some people were not able to get out," Mr Agudong told radio station DZBB. "I pity the children. We saw dead bodies on the side, and some being rescued."
It is believed 58 babies were among the passengers on board but it is unclear how many of them died.
Many of the survivors were sick from swallowing seawater and oil that is thought to have spilled from the 11,000-tonne ferry.
The authorities believe it is possible some people may have been picked up by local fishing boats and have not yet reported themselves.
A coast guard official told reporters that the cargo ship, Sulpicio Express 7, had 36 crew members on board, but it did not sink.
It emerged on Saturday that Span Asia Carrier Corp, the company that owns the cargo ship, also owned the ferry involved in the world's worst maritime disaster in peacetime, which occurred in the Philippines in December 1987.
More than 4,000 people died when the Dona Paz ferry collided with a tanker.
Maritime accidents are quite frequent in the Philippine archipelago because of tropical storms, badly maintained passenger boats and weakly enforced safety regulations.
Passengers on the ferry involved in Friday's collision had embarked at Nasipit in the southern province of Agusan del Sur.
The 40-year-old vessel was operated by a Chinese-owned company called 2Go, the largest ferry operator in the Philippines.