Pope Leo XIV on Sunday returned to the balcony where he was presented to the world as the new leader of the Roman Catholic church just days ago, using his first Sunday address to the faithful to call for peace.

“Never again war,” he said to a roar from the massive crowd that had gathered in St. Peter’s Square, an appeal he addressed to the world’s most powerful leaders. He noted that it was almost 80 years to the day that the “immense tragedy” of World War II ended and quoted Pope Francis, his predecessor, who often referred to the current wave of violence globally as “a third world war in pieces.”

Leo called for an “authentic, just and lasting peace” in Ukraine and the freeing of all prisoners in that war. The pope said that children should be returned to their families. Although he did not specify which children he was referring to, many Ukrainian children have been taken to Russia during the war against their family’s wishes.