BAGUIO, Philippines -- At least 13 people died when the van they were riding in plunged into a deep ravine in the mountainous northern Philippines, officials said Sunday.

The van veered off a mountain road in remote Buguias town in Benguet province on Saturday and plummeted into a 90-meter (295-foot) deep ravine, initially killing 10 people. Two more victims died later Saturday and another victim died in a hospital on Sunday, Benguet Governor Nestor Fongwan said.

Five other people survived with injuries, Fongwan said by telephone, adding one of the 19 people in the van managed to jump out before the van went over the cliff.

The victims were mostly members of a family who attended an election victory party for a town mayor. Investigators were trying to determine if the driver, who was among the survivors, was at fault or if the van he was driving had mechanical defects, Fongwan said.

Fog apparently hampered road visibility at the time of the accident, police officer Jefferson Lopez said.

The accident was the deadliest so far this year in the northern region, a scenic agricultural and tourist destination 250 kilometres (155 miles) north of Manila where many mountain roads lack railings, lights and safety signs.

Reckless driving, neglected vehicles and roads, and poor enforcement of traffic laws have been blamed for the many deadly road accidents in the Philippines.