Pope Leo, the first US-born leader of the global Catholic Church, prayed on Sunday that God would "stop the pandemic of arms" after a mass shooting on August 27 at a Minnesota Catholic school that killed two children.
"Our prayers (go) for the victims of the tragic shooting during a school Mass in the American state of Minnesota," Leo, speaking in English, said in a weekly prayer with crowds in St. Peter's Square.
"Let us plead God to stop the pandemic of arms large and small, which infects our world," said the pope.
Leo was elected pope by the world's cardinals in May after the death of the late Pope Francis. He has shown a different style from his predecessor, rarely speaking off the cuff and usually preferring a more cautious tone in his public appeals.
Addressing the world in his native English
Sunday's appeal was also a rare instance of the pope addressing a world event in his native English. Leo usually prefers to use Italian, the language of the papacy.
The Minneapolis shooter, Robin Westman, identified as a trans woman and changed her name to Robin from Robert in 2020.
The YouTube channel, which has since been deleted, showed Westman's collection of guns and weapons, on which 'six million wasn't enough,' and 'extra Jew gas,' were written, in reference to the Holocaust.
Corrine Baum and Shir Perets contributed to this report.