Guatemala City (AFP) – At least 51 people were killed in Guatemala City on Monday when a bus crashed through a guard rail and plunged into a ravine, rescuers said, one of the worst road accidents in Latin America in years.

The municipal fire department said the bodies of 51 people were retrieved from the wreckage of the bus, which was carrying more than 70 people when it crashed off a bridge into a river contaminated with effluent.

Victor Gomez, spokesperson for the Volunteer Firefighters group that was involved in the rescue effort, confirmed that there were “51 bodies in the provisional morgue.”

Rescuers had already managed to extricate 10 injured people from the wreckage.

The fire department said the driver lost control of the bus and collided with several small vehicles before plunging over the precipice.

“The bus kept going, broke through a metal railing, and fell into a ravine about 20 meters (65 feet) deep until it reached the sewage-contaminated river,” the department’s Carlos Hernandez told reporters.

Communications Minister Miguel Angel Diaz said an initial investigation showed that the bus was 30 years old but still had a license to operate.

He said that the cause of the early morning accident was still unknown and that investigators were looking into whether the bus was overloaded with passengers.