Two passenger buses have crashed head-on along a new highway in Bolivia, raising the country's three-day bus crash death toll to 56, AP reported.

Police say Thursday's crash killed 17 people and injured 34 near the eastern town of Taperas along a newly built highway to Brazil.

Officials say 18 people died on Monday when a bus plunged into a flood-swollen river near the capital of La Paz.

Twenty-one died when a bus ran off a road on a hill near Challapata in southern Bolivia.

Bad roads, bad drivers, poorly maintained vehicles and heavy rains contribute to many crashes.