MANILA, Philippines (AP) — An explosion and fire on a wooden fishing boat at sea killed six Filipino crewmembers while six others were rescued in the nighttime darkness, coast guard officials said Thursday.

The survivors, including the skipper of the F/B King Bryan, were still being treated at a hospital or were too traumatized to tell investigators what set off the explosion Wednesday night about 8 kilometers (5 miles) off Naga city in Cebu province, coast guard officials said.

One of the injured crewmen was in critical condition at a hospital, the coast guard said.

Video and pictures issued by the coast guard show flames and smoke billowing from the fishing boat as rescuers scanned the waters in the darkness. Crewmembers with burn injuries are carried to safety by coast guard personnel.

The wooden-hulled boat, which had bamboo outriggers, apparently developed engine trouble before an explosion and a fire engulfed the vessel, injuring crewmembers and forcing others to jump into the sea in panic. A passing tugboat helped put out the blaze and a coast guard search and rescue operation was launched, coast guard officials said.

Sea accidents are common in the Philippine archipelago because of frequent storms, poorly maintained boats, overcrowding and spotty enforcement of safety regulations.

In December 1987, an overcrowded ferry, the Dona Paz, sank after colliding with a fuel tanker, killing more than 4,300 people in the world’s worst peacetime sea disaster regarded by some as Asia's Titanic.