LIMA, Peru — A makeshift bus carrying 51 Quechua Indians back from a party in southeastern Peru plunged off a cliff into a river, killing everyone on board, including 14 children, rescue workers said Saturday.

The accident occurred Friday night as the bus, which was actually a cargo truck, made its way back from the provincial capital of Santa Teresa, an area about 310 miles southeast of Lima. It went off the road and fell about 650 feet into a deep ravine, ending up in the Chaupimayo River.

“We haven’t found a single survivor,” said Capt. David Taboada, a firefighter who was leading the rescue operation. The cause of the accident had not been determined, he said.

Fedia Castro, the mayor of the district where Santa Teresa is, told Canal N, a Peruvian television network, that rural farmers must rely on informal means of transport, like the cargo truck, because of a lack of public buses.