The FA, West Ham and police are launching investigations into the scenes of violence that surrounded Tuesday night's Carling Cup game between the Hammers and Millwall.
Manager Gianfranco Zola signalled his disgust at the scenes: "I've been involved in difficult games and things happened. Here, I've played seven years and I've never seen it like this. I was completely shocked. Totally."
Police made several arrests and are scanning CCTV footage to identify hooligans. FA director of communications Adrian Bevington outlined the FA's approach to their investigation to the BBC: "We have to understand exactly what measures were put in place last night. I'm not going to condemn West Ham or Millwall football clubs for any of their actions - certainly not at this stage, because we don't know exactly what's been put in place.
"And we know there have been huge efforts on the parts of all our clubs to try to eradicate the problems and we've had a history of success on that. However, we have to make sure that the individuals concerned face such tough actions that they can't go to football again.
Sports Minister Gerry Sutcliffe has labelled the scenes as "a disgrace to football. We have made great progress in the past 20 years in tackling football hooliganism in this country and we will not tolerate any return to the dark days of the 70s and 80s when it plagued the game. We will never be complacent in the fight against football violence."
The Hammers have issued a statement vowing to punish those responsible for the "deplorable scenes" The club will not tolerate the unacceptable behaviour witnessed inside the Boleyn Ground and will take the strongest possible action against anyone found responsible, including life bans.
"As was the case before, during and after the match, we are co-operating fully with the relevant agencies, including the police."
Police Chief Superintendent Steve Wisbey said: "Incidents of this nature at a match are thankfully rare, but it would appear that a small number of supporters were intent on causing a confrontation."
Millwall boss Kenny Jackett had defended his club's fans' part in the trouble. "I didn't fear for my own safety. There were no Millwall fans on the pitch. They stayed where they were supposed to," he said but a Lions official statement promised to ban for life any supporter identified as being involved in "criminal activity" and to assist the FA in their enquiries.