Seventeen people were killed and 30 others injured in the fourth serious accident on Bolivia’s roads in a week, authorities said Thursday.

Two buses collided head-on late Wednesday night near the village of Taperas, about 310 kilometers (193 miles) east of the eastern metropolis of Santa Cruz, the police chief in Chiquitos district told online publication El Deber.

“Up until now we have counted 17 deceased people, unfortunately,” Col. Rene Calla said. “The injured people that have been transported since last night to the hospital in San Jose are approximately 30.”

Rescue and recovery efforts continued at the accident scene.

The spate of deadly crashes began last Friday, when eight people died in a wreck in Santa Cruz province.

On Monday, a bus ran off a mountain road in La Paz province and fell 400 meters (1,311 feet) into a river, leaving 18 dead, 25 injured. Eleven other people remain missing and witnesses said some bodies were swept away by the current.

More than 20 people were killed Wednesday and 30 others injured when a bus plunged into a ravine in Oruro province.

Bolivia, the poorest nation in South America, suffers an average of 1,000 traffic fatalities every year, many of them attributed to the generally poor quality of roads.