LA PAZ — A public bus careened off a winding road and plunged some 100 meters (330 feet) into a ravine early Monday in southern Bolivia, near the Argentine border, killing at least 28 people, and leaving 10 injured, officials said.

An investigation has been launched into the crash, said transport officials in the city of Tarija, 570 miles (919 km) from the capital, but initial findings were that poor visibility was a major factor in the accident.

The bus, reportedly carrying some 70 passengers -- well over the legal limit -- was en route from the border town of Villazon to Tarija, when it came off the road at steep section of the road known as Cuesta de Sama.