A heavily armed shooter opened fire Wednesday on schoolchildren attending a church service in Minneapolis, killing two pupils and wounding 17 people in the latest violent tragedy to jolt the United States.

Minneapolis City Police Chief Brian O¡¯Hara said that the attacker sprayed bullets through the windows of the Annunciation Church as dozens of young students were at a Mass marking their first week back at school.

The church sits next to an affiliated Catholic school in Minneapolis, the largest city in the Midwestern state of Minnesota.