Pope Francis issued his first tweet on Sunday shortly after performing his first Angelus prayer, with a consistent message: "Pray for me".
"Dear friends, I thank you from my heart and ask you to continue to pray for me," the Argentine pope tweeted from the @Pontifex account.
The first Latin American pope made the same appeal when he appeared a few minutes earlier before more than 150,000 people massed in St Peter's Square for his first Angelus prayer.
"Thank you for your welcome, and for your prayers," Francis said. "Pray for me."
The Vatican used the papal Twitter account shortly after Francis's surprise election last Wednesday to tweet "Habemus Papam Franciscum" (We Have Pope Francis).