LA PAZ - A truck traveling on a highway in Southern Bolivia collided with a bus early on Monday morning, forcing the bus off the road and killing at least 31 people, police said.

Speaking to reporters, police spokesperson Limbert Choque confirmed the death toll, which he said included both men and women, as ambulances and emergency vehicles arrived at the scene of the accident. Another 22 people suffered injuries.

President Luis Arce expressed condolences for the victims on social media.

"This unfortunate event must be investigated to establish responsibilities," he said in a post on Facebook. "We send our most sincere condolences to the bereaved families, wishing them the necessary strength to face these difficult times."

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Police said the bus rolled some 500 meters down a ravine after the collision, which took place on the highway between Oruro, in the Bolivian Altiplano, and the highland mining city of Potosi.

The driver of the truck has been arrested, police added, while the cause of the accident is under investigation.

The crash comes just days after more than three dozen people were killed in the same region after two buses collided.