LIMA (AFP) - At least 23 people were killed and 32 injured on Friday when a bus plunged into a river in the Andes mountains in southeastern Peru, police said.

"The bus ended up nearly completely submerged in the river. That made the rescue brigade's work difficult," said police spokesman Linio Sanchez of the town of Urcos, in the tourist-magnet region of Cusco.

The overnight bus departed from the city of Puerto Maldonado on Thursday and was carrying passengers to the city of Cusco, some of whom were on their way to vote in Peru's presidential election Sunday.

It went hurtling into the Mapacho river in a sparsely populated rural area.

The injured were taken to hospitals in Cusco and a nearby town.

Fatal road accidents are common in Peru, in part because of lax traffic enforcement but also because of the Andean country's challenging mountain terrain.

On Jan 18 at least 16 people were killed and 10 injured when a bus plunged off a curvy mountain road into the Tarma river in the central region of Junin.