MANILA -- Investigators are looking into witness accounts that a squall or sudden violent winds caused 3 ferries to capsize off the central island of Guimaras and Iloilo provinces over the weekend, the Philippine Coast Guard said Monday.

At least 28 people were killed when the motorized, wooden-hulled boats capsized, PCG spokesman Commander Armand Balilo said, adding that the search continues for 3 more people.

"Ang naging cause na sinasabi ay iyung biglang lakas ng alon o iyung squall. Ang sabi nga doon sa maritime community, iyung 'subasko' na tinatawag... May mga bahay din na naapektuhan nitong parang ipo-ipo na tumama sa area," he told radio DZMM

(The supposed cause is the sudden swelling of the waves or squall. The maritime community calls this locally as 'subasko.' There were houses that were destroyed before the tornado of sorts hit the area.)

Two of the ferries were carrying 45 and 40 passengers, below their capacity of 47 and 44, respectively, said Balilo.

A third ferry was not carrying passengers and all of its 5 crew members survived, he said.

Watch more in iWantv or TFC.tv

The weather bureau had not raised a gale warning in the area before the ferries ventured off to sea, said the official.

"Iyung tumamang hangin at alon sa kanila, talagang hindi po na-predict ito," Balilo said.

(The wind and wave that hit them were not predicted.)

The number of casualties from the coast guard is higher than the death toll being reported by the Iloilo disaster agency, which was at 28.

Scores of people die each year from ferry accidents in the Philippines, an archipelago of 7,100 islands with a poor record for maritime safety. With a report from Reuters