Children as young as 10 have been caught up in fan violence following a Championship match.
Over 200 supporters of Middlesbrough and Sheffield United clashed following their game on Saturday evening, according to Cleveland Police.
Police say five people have been arrested so far and more are expected in the coming days.
The violence began after United fans invaded the pitch to celebrate a late goal, which was disallowed, and then continued outside the ground in the car park.