MANILA, June 17 (Xinhua) -- Six people were killed and 20 others injured after a truck carrying solar farm workers on Tuesday plunged into a ravine in Pangasinan province, the northern Philippines, police said on Wednesday.

Police said the accident occurred shortly after 6 p.m. on Tuesday in Labrador town when the truck's brakes reportedly malfunctioned, causing the driver to lose control while descending a curve along a mountain trail.

The truck, which was transporting workers to a solar farm, first collided with a pickup truck carrying 12 passengers before veering off the road and plunging into the ravine.

Rescue and investigation are still underway.