Saturday's Championship clash between West Bromwich Albion and Millwall was marred with unsavoury scenes of violence.
A video on social media shows fans of both sides clashing in an incident which is thought to have taken place at half-time during yesterday's game.
The match at the Hawthorns finished 1-1, with Daniel Ballard cancelling out Kyle Bartley's opener. Karlan Grant had earlier missed a penalty for the hosts but the result was enough to send them top of the Championship table.
But the talking point in the days to come is likely to be the ugly clash between the two sets of fans.
The video appears to show a gate being broken during the brawl. There is no evidence of any police presence to break up or calm the situation down.
One scene appears to show a supporter laid out unconscious, believed to be a Millwall fan. He is quickly tended to by fans who attempt to save him from the ongoing melee.
Bottles are also chucked over the separating barrier, from fans on either side, whilst a separate video shows huge numbers charging towards the fence seemingly in an attempt to force it down.
Police chiefs have said they are now searching for those involved in the ugly scenes.
Chief Inspector Ian Gorman, from West Midlands Police said: "We're sad to say that there were pockets of fighting at the match on Saturday.
"Video of some of these fights was uploaded onto Facebook and Twitter which we're using along with our own images and the club's CCTV to find those responsible.
"People found guilty of crimes at fixtures face lifetime match bans as well as the sentences handed down by the courts.
"Anyone who can help our investigation into violence at the West Brom v Milwall game should contact us via Live Chat on our website west-midlands.police.uk."
Valerien Ismael's side are top of the Championship
A spokesperson from West Brom said: "We are aware of an incident which took place during the interval of yesterday's fixture against Millwall, and a full review has begun in conjunction with West Midlands Police.
"We will work with police and Millwall Football Club to ensure anyone responsible for the disorder receives the appropriate punishment."
Millwall were contacted for comment by the Mirror.
Despite the penalty miss seeing them ultimately miss out the three points, Albion remain unbeaten since relegation from the Premier League.
Boss Valerien Ismael said afterwards: "We need to have another desire and another attitude to be better than this. We have to be more ruthless in our backline - that was our strength in the first five games so we need to get back to that and dominate our opponent.
"We will learn from this and adjust but we need to adapt from when the opponent does not want to take any risk and wants to take the intensity out of the game.
"The game plan from the opponent was another way we have to deal with and Millwall made it difficult for us."
West Brom and Millwall have been contacted for comment.
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