Three relatives of Pope Francis died and a fourth was in critical condition Tuesday after a car crash on a provincial highway in Argentina, the Vatican and a local police official said.

The small car carrying a nephew of the pope along with the man's wife and two young children slammed into the back of a truck, said Highway Police Superintendent Jorge Raineri. The wife and children, one 2 years old and the other 8 months, were killed.

Emanuel Bergoglio, the 38-year-old son of a brother of Pope Francis, was hospitalized. He suffered extensive injuries and his condition was not considered stable, said Ignacio Bruno, an assistant director of the hospital in the town of Villa Maria, to Todo Noticias television.

The man's 36-year-old wife, Valeria Carmona, and two children, Jose and Antonio, had already died by the time they arrived at the hospital, Bruno said.

The accident occurred between the cities of Rosario and Cordoba, apparently as the family was returning to Buenos Aires following a holiday weekend. The driver of the truck was not injured.

Vatican spokesman the Rev. Federico Lombardi said "the pope was informed about the tragic accident. He is deeply pained." He added the pope asks "all who share in his grief to unite with him in prayer."