Southend United have condemned the fans who caused trouble during Saturday's Essex derby against Colchester United at Roots Hall.
Police have already launched an investigation after a lone Southend fan was filmed jumping onto the pitch and running over to confront a stand full of Colchester supporters towards the end of the sold-out League 1 clash, which the hosts won 3-0.
Southend have now asked for assistance in identifying the individuals involved in the trouble and have vowed to take "very strong action" against them.
A statement read: "The club want to reassure supporters that they view this incident as completely unacceptable and something which does not represent supporters of either club or indeed football fans. Such incidents have no place in football.
"Southend United completely condemn the actions of these few mindless individuals who appear to have done this for personal glorification, we are already working with the authorities and the club will be taking very strong action against anyone who came onto the pitch or attacked the away fans."
Chief executive Steve Kavanagh added: "Such people are not welcome at Roots Hall and I hope all fans will assist the club in identifying them to ensure that their actions do not go unpunished.
"The incident on Saturday is something that hasn't occurred in recent memory and the club will do everything we can to ensure Roots Hall continues to remain a safe and family friendly environment for football fans."