Police had to separate West Ham and Middlesbrough fans after they clashed during disturbances outside the Hammers' new London Stadium.
Officers had to intervene when violence flared in the Olympic Park following the 1-1 draw between the two Premier League clubs.
Police escorted Middlesbrough fans away from the stadium while cordoning off some West Ham supporters.
The trouble followed recent crowd disturbances inside the stadium.
At the first Premier League match at the venue - against Bournemouth on 21 August - some fans arrived with tickets for seats that did not exist, while fighting broke out between rival supporters outside the stadium.