"I thank you for your condolences for what happened in my family," Francis said. "Even the pope has a family."
Later in the day, Argentine President Cristina Fernandez de Kirchner telephoned Francis to express "condolences from her and from the Argentine people," the Vatican said.
The 77-year-old pope listened as priests expressed condolences in several languages during his weekly public audience at the Vatican.
Francis then explained about his family. "We were five siblings. I have 16 nephews and nieces and one of these nephews had a car accident and lost his wife and two little ones and is in critical condition. I thank you very much for your condolences and prayers."
"I greet the San Lorenzo champions," Francis said, smiling broadly. The club is "part of my cultural identity."
He shook hands with team members, who brought along the trophy, and grinned when he was given a red-and-blue team jersey and posed for photos with them.