The bus operated by the company Potosi left Villazon, Bolivia, on Friday night and was traveling on a route to Buenos Aires when the crash occurred in the province of Jujuy, prosecutor Alejandro Maldonado said.
Maldonado said six of the 10 victims had been identified by Saturday evening, including two Germans identified as Sophie Colombine Aring and Herman Schneider. He said the other four victims identified so far were Bolivians.
Police said a 6-year-old girl and a 6-month-old girl were among those killed.
The bus was carrying 69 passengers as well as two drivers and another employee, Maldonado said by phone from Jujuy province.
"The vehicle fell into a ravine of about 200 meters (650 feet)," he said.
The rugged location as well as the badly wrecked bus and scattering of passengers' bags and documents complicated the task of identifying victims, Maldonado said.
"We're trying, with the help of the Bolivian consul and some of the relatives, to establish the identity of all the deceased people," the prosecutor said.
The cause of the crash was still under investigation.
The Argentine news agency Infobae said the 69 passengers were mostly Bolivians but included three Peruvians, three French people, two Germans, a Panamanian, a Spaniard and a British citizen.