Haunting images have emerged showing children at Annunciation Catholic School in Minneapolis beaming as they started their school year just days before a gunman murdered two children there.

The students were seen smiling in a group picture in their school uniforms in images shared on social media on Monday, which the school captioned #AFutureFilledwithHope.

In another image, the children gathered around a school cafeteria lunch table as one sat with her arm in a cast.

The happy pictures were shared to social media just two days before Wednesday's mass shooting, where dozens are feared to have been shot at a church service to mark the beginning of the school year.

Two children aged eight and 10 were killed in the attack and at least 17 others - 14 children and three adults - were injured.