A ferry with 700 passengers on board has collided with a cargo ship near the Philippine city of Cebu, according to the coastguard.
The coast guard said the MV Thomas Aquinas listed and began sinking after hitting the Sulpicio Express Seven Cargo vessel and the captain ordered the ship abandoned.
Officer Joy Villegas said the collision occurred on Friday evening close to the shore near the central city of Cebu. The ferry was travelling from Cebu to Manila.
She said at least 17 people were confirmed dead and around 525 rescued.
Two rescue vessels have been dispatched and other nearby boats were helping to pull passengers from the water.
There has been no official confirmation of casualties but passenger Jerwin Agudong told radio station DZBB people were trapped on the ferry and he had seen bodies in the water.
He said: "It seems some were not able to get out. I pity the children. We saw dead bodies on the side, and some being rescued."
Hundreds of passengers jumped into the ocean as the ship started to sink, according to survivors. Many of the passengers were asleep and others struggled to find their way in the dark.
Accidents at sea are common in the Philippine archipelago because of frequent storms, badly maintained boats and weak enforcement of safety regulations.
In 1987, the ferry Dona Paz sank after colliding with a fuel tanker in the Philippines, killing 4,341 people in the world's worst peacetime maritime disaster.
In 2008, the ferry MV Princess of the Stars capsized during a typhoon, killing nearly 800 people.