(Updates number killed and rescued, adds quotes)
By Manuel Mogato
MANILA, Aug 17 (Reuters) - Thirteen people died and 690 were rescued after a ferry sank following a collision with a cargo vessel in the central Philippines, a coastguard commander said.
"We don't know if there are still people missing," Rear Admiral Luis Tuason told local radio early on Saturday, citing a discrepancy between the actual numbers killed or rescued and the ferry's manifest, which showed 692 crew and passengers on board.
The 40-year-old ferry St Thomas of Aquinas is allowed to carry up to 904 passengers.
The collision happened before 9 p.m. local time (1300 GMT) off Cebu Island.
Tuason said the cargo vessel Sulpicio 7 was on its way to Davao when it collided with the ferry from Mindanao, which was supposed to pick up more passengers in Cebu before proceeding to Manila.
"Passengers jumped over board after the ferry listed but it was too dark and that made it difficult to find people in the water," Tuason said.
Local officials said the ferry sank about 1 km (1,100 yards) from shore. Local radio said many people were plucked from the waters by dozens of fishing boats that rushed to the area. They were taken to local hospitals.
The Philippines was the site of the world's worst peacetime sea disaster in December 1987. The ferry Dona Paz sank after colliding with the tanker Vector in the Sibuyan Sea, killing 4,375 on the ferry and 11 of the Vector's 13-man crew. (Reporting by Manny Mogato, editing by Mark Trevelyan)