Police are appealing for the victim of an assault outside Hull Paragon Station to contact them.
A station security guard reported that he had intervened in an assault on a female teenager in the Anlaby Road car park on Friday September 28 at 9.45pm.
Following the assault, the victim is believed to have left the station, telling security staff that she would contact police the following day to report the incident, but never did.
Pc Mark Lambert, the investigating officer, said: "The victim has yet to get in touch with us in relation to this assault. We have viewed the CCTV of the incident which clearly shows she was subjected to an aggressive assault."
Footage shows her being kneed in the face and dragged to the floor then kicked and punched by two other teenage females, leaving her with a bloody nose.
"The victim must have been left extremely scared and shaken following this nasty assault, and we would really like to hear from her to check she is okay and offer her our support," Pc Lambert said.
The victim is urged to contact British Transport Police confidentially on 0800 40 50 40.
Copyright Press Association 2012