Seven people have been arrested following ugly clashes between West Ham United and Chelsea fans at the London Stadium on Wednesday night.
The Metropolitan Police said it "will work tirelessly to identify people involved and bring them to justice" after West Ham's 2-1 victory over the Blues in the EFL Cup was barred by fan violence inside and outside the stadium.
"Although the vast majority of people left the stadium peacefully and were well behaved, there were a minority of people who attended the match who were clearly intent on being involved in confrontation and violence," said Met Police commander BJ Harrington.
"There were unacceptable incidents inside and outside the stadium, before, during and after the game."
West Ham, who have been beset by problems with crowd disturbances since moving into the London Stadium at the beginning of this season, threatened to issue life bans to fans found to have been involved in scenes requiring police in riot gear to enter the fray.
Fans threw seats and coins at each other across a segregated area of the ground, while some broke through security stewards to get at each other at the top of the Sir Trevor Brooking Stand.
"West Ham United and London Stadium partners unreservedly condemn the behaviour of individuals involved in incidents during this evening's fixture with Chelsea," said West Ham in an official club statement.
"Once identified, those found to have acted improperly will be banned from attending any West Ham United fixtures for life and we will request the courts to serve banning orders to prevent these individuals attending any other football."
Chelsea said: "The club is extremely disappointed to see disturbances at the end of tonight's game and we condemn such behaviour."