TWO girls, aged 11 and 14, have been charged for confining and violently assaulting a teenage girl.

At 5.45pm on Wednesday, police patrols in a northern suburb were directed to an injured teenage girl near a fast-food outlet.

She was taken to hospital for treatment of multiple injuries, and soon after police were provided with a video.

The video showed the forcible confinement and a prolonged and violent assault of the girl.

The attackers, aged 11 and 14, confined the third girl before repeatedly punching, kicking and kneeing her. They also threatened the girl with further assaults if she spoke about the assault.

The two girls believed to be responsible for the assault were identified by police and arrested in their homes.

Both girls have been charged with assault occasioning actual bodily harm, joint commission forcible confinement and threatening a participant in a criminal investigation.

Police are urging any witnesses to the assault to call 1800 333000.