There has been a tragic shooting at a church on the south side of Minneapolis.

Two children, aged 8 and 10, were killed after a lone gunman fired shots from outside the Annunciation Catholic Church, where dozens of children and staff from nearby Annunciation Catholic School were attending a morning mass as part of back-to-school celebrations.

Seventeen other people, including 14 children, were injured.

Minneapolis Police say two of the victims are listed in critical condition.

Police say the gunman was found dead at the rear of the church with a rifle, shotgun and handgun in his possession.

A smoke bomb was also discovered.

“This was a deliberate act of violence against innocent children and other people worshiping,” says Minneapolis Police Chief Brian O’Hara.

“The sheer cruelty and cowardice of firing into a church full of children is absolutely incomprehensible.”

Little is known about the shooter.

O’Hara says he was in his 20s with no known criminal history, but it is not immediately known if he was connected to the school or church.

Police are still investigating to determine the motive behind the shooting.