Three of Pope Francis' relatives were killed and one was critically injured after a car crash in Argentina early Tuesday morning, the Vatican said.

The pontiff's nephew was driving with his wife and two young children north east of the capital Buenos Aires in Cordoba when he slammed into the back of a truck, Highway Police Superintendent Jorge Raineri told the Associated Press.

The wife and her children, a 2-year-old and and 8-month-old, were killed. Emanuel Bergoglio, the pope's 38-year-old nephew, suffered severe injuries and was in placed in a medically induced coma in the hospital's intensive care unit, police told NBC News. His injuries include liver trauma and a cracked femur.

Vatican spokesman Father Federico Lombardi said "the pope was informed about the tragic accident.

"He is deeply pained," Lombardi told the AP. He asks "all who share in his grief to unite with him in prayer."

Bergoglio, the son of Pope Francis' brother, was apparently traveling with his family back to Buenos Aires after a weekend vacation.

His wife is identified as 36-year-old Valeria Carmona, who was killed along with their 8-month-old son Jose during the crash between the cities of Rosario and Cordoba shortly after midnight, police said. The 2-year-old son, Antonio, was taken to the hospital but later died, NBC News reported.

The driver of the truck was not injured, according to the AP.

The incident comes a day after the pope joked he might die soon, NBC News reported. Pope Francis responded to questions about his widespread popularity by saying it will not last forever.

"This will last a short time, two or three years, and then to the house of the Father," he said.