Over 30 people have been killed in an accident where a bus plunged down a ravine in northern Peru, police say.Police sources said the accident took place on Saturday, when the bus veered off a mountain road near the city of Otuzco, some 570 kilometers (about 350 miles) north of the capital, Lima. Thirty-three people died and ten others were injured. Police blamed the region’s treacherous, winding roads, the vehicle’s poor condition and driver error for the deadly accident. A local resident said it seemed that the driver had fallen asleep behind the wheel prior to the accident. On March 9, another bus plunged down a mountain gap some 180 meters (about 585 feet) in southern Peru, killing 14 people and injuring 36 others. Road accidents are common in the Peruvian Andes mountain range due to poor maintenance of roads and vehicles and the tendency of overworked bus drivers to speed. According to the latest official figures, there were more than 1,100 reported highway accidents in Peru in 2011, which resulted in over 1,120 deaths and nearly 2,600 injuries.