Officials said an 8-year-old and a 10-year-old were killed in the shooting at Annunciation Catholic Church. Two more children were in critical condition.

Aimee OrtizMichael Levenson and Glenn Thrush

A gunman fired a rifle through the windows of a Catholic church in Minneapolis where students were celebrating their first Mass of the new school year on Wednesday, killing an 8-year-old and a 10-year-old in the pews and injuring 17 others, the police said.

The attacker then shot and killed himself in the rear of the church, the Minneapolis police chief, Brian O’Hara, said at a news conference. Of the 17 people injured, 14 were children, the chief said. Two were in critical condition, he said.

The shooting, at about 8:30 a.m. Central time, took place at the Annunciation Catholic Church, which has a school for children from prekindergarten through eighth grade. Monday was the first day of school, and the all-school Mass on Wednesday is an annual tradition.