Three relatives of Pope Francis, two great nephews and their mother, have been killed in a traffic accident in Argentina, police said.

The dead from Tuesday's crash include a baby aged eight months and a two-year-old toddler, police commissioner Carina Ferreyra said. The vehicle in which they were travelling collided with a lorry, the police said.

Their father, the pope's nephew Emanuel Horacio Bergoglio, was in serious condition, she told the AFP news agency.

Vatican spokesman Federico Lombardi said the pope had been informed about the accident and was "deeply pained."

"He asks all those who share in his pain to join him in prayer," Lombardi added.

The accident happened on a highway after midnight in the central province of Cordoba.

For reasons that are under investigation the car hit a truck carrying grain from behind. Bergoglio is in hospital with multiple injuries. Official details of his condition have not been released.

The truck driver, a 60-year-old man, was not hurt.

Bergoglion is the son of Alberto, the pope's late brother.

Source: Agencies