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

The boys were aged eight months and two, police commissioner Carina Ferreyra said.

Their father, the pope's nephew Emanuel Horacio Bergoglio, is in serious condition, she added.

The accident happened after midnight local time in the central province of Cordoba.

It is understood the car hit a truck from behind.

Mr Bergoglio is the 38-year-old son of Alberto, the pope's late brother.

Both he and his two-year-old son were pulled from the wreckage alive and taken to hospital 30km away where the child died shortly after being admitted.

The crash occurred near the city of James Craik about 550km northwest of the capital, Buenos Aires.

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," he added.