Horrifying footage has emerged from inside the Annunciation Catholic School and Church showing children fleeing as a crazed gunman opened fire.

The grim clip, obtained by CNN, shows dozens of kids sprinting to the exit in Minneapolis on Wednesday as Robin Westman fired shots inside.

They can be seen anxiously leaving the place of worship as one adult asks: 'Where is the shooter?'

Some look to be hunched over as if to keep a low profile over fears anymore bullets would be fired at them. Others also covered their ears as blasts rang out.

Two young children, aged 8 and 10, were killed in the shooting while 18 other victims - 15 of which were children - were wounded.