The bus fell all the way to the bottom of a 400-metre ravine, leaving bodies scattered across the slopes of a hill in the desert region, press reports say.
A bus carrying miners has plunged into a ravine on a mountain road in southern Peru, killing at least 27, according to their employer.
The Ares Mining Company said the bus was headed from a pit near the Nasca Lines archeological site to the city of Arequipa.
The bus fell all the way to the bottom of a 400-metre (1,300-foot) ravine, leaving bodies scattered across the slopes of a hill in the desert region, press reports said.
One official said the driver may have fallen asleep at the wheel.
The miners had been on the job for weeks and were headed home to rest, the company said.
There were 16 injured being treated at Nasca hospital, RPP radio said.
"My brother was ejected through the window and fell on stones. He is wounded and cannot move his body. They are going to transfer him to Lima" to continue his treatment, a woman named Adriana Cruz Taipe told reporters.
'Very dangerous area'
The mining company initially said all of those killed were miners but a prosecutor in the town of Puquio, Jhonny Romero, said the fatalities included the driver of the bus, who he said may have fallen asleep.
"This is a very dangerous area. Sleep may have been the cause of the accident," Romero said.
It was the second major road accident in 10 days in Peru, where driving can be dangerous due to speeding motorists, poorly-maintained highways, a lack of signs and poor traffic safety enforcement.
A total of 17 people died last week when a bus plummeted into a ravine in the La Libertad region, 500 kilometres (300 miles) north of Lima.
According to the Ministry of Transport, between January and November 2020, 3,526 traffic accidents were registered on Peruvian roads.