Mayor Jacob Frey of Minneapolis shook his fist in sorrow and anger, spitting out words before the hastily assembled television cameras.

“Don’t just say this is about thoughts and prayers right now,” he said on Wednesday, referring to the three words invariably echoed by politicians after mass shootings. “These kids were literally praying. It was the first week of school. They were in a church.”

Images of American school shootings have become all too routine, a blur of anguished parents, uniformed police officers and traumatized students fleeing school buildings with small hands raised in the air.

But for the city of Minneapolis, which has weathered trauma on trauma of late, that morning’s attack on students gathered for Mass at Annunciation Catholic Church was, in the mayor’s words, “unspeakable.” It left the city and the country with a picture that was uniquely shocking and violent: A gunman aiming through a church window at children assembled inside, firing dozens of rounds while they dove for cover beneath the sturdy wooden pews.

“My heart is broken as I think about students, teachers, clergy and parishioners and the horror they witnessed in a church,” said Archbishop Bernard A. Hebda of St. Paul and Minneapolis, “a place where we should feel safe.”

Two children, ages 8 and 10, were killed. Fourteen others and three adults were wounded.

Minneapolis is a big city accustomed to gun violence. But the Twin Cities have suffered more than their share this summer, including the assassination of State Representative Melissa Hortman and her husband, the wounding of a Democratic state senator, John A. Hoffman, and his wife, and a spasm of gun violence just this week. The city has been tested by the murder of George Floyd in 2020, by the ensuing riots and fires, and by recurring urban and political trauma.