SRINAGAR, India (AP) — A bus carrying soldiers fell into a gorge in India’s remote Ladakh region on Friday, killing at least seven and injuring 19 others, officials said.

The bus plunged off a mountainous road and rolled down the 25-meter (80-foot) -deep gorge in the frigid region’s Nubra Valley, police said.

The injured soldiers were flown to a military hospital in the northern city of Chandigarh, the military said.

Authorities were investigating whether the accident was caused by a mechanical failure or driver negligence. The privately owned bus was hired by the military to transport soldiers in the high-altitude region.

The accident occurred near an area where the borders of India, Pakistan and China meet, in what strategic experts call the world’s only three-way nuclear-armed junction.

India has the world’s deadliest roads, with hundreds of thousands of people killed and injured annually. Most accidents are blamed on reckless driving, poorly maintained roads and aging vehicles.