Newcastle manager Alan Pardew has accused the supporters who invaded the pitch during the team's pre-season friendly at Darlington on Friday of "truly appalling behaviour".
Pardew claimed the fans, who were responsible for causing a 10-minute delay in the match as celebrations of Sammy Ameobi's 55th-minute goal turned ugly, had brought shame on the club.
Pardew said: "Having reflected overnight on yesterday's match at Darlington that was interrupted in the second half by the actions of some of our supporters, I am left bitterly disappointed by the events that unfolded after Sammy Ameobi scored our second goal."
The match, which United won 2-0, looked in danger of being called off as scenes turned violent at The Darlington Arena and, although calm was eventually restored, the guilty parties can expect repercussions. Three fans were arrested and another escorted from the ground.
Pardew added: "Apart from the frustrating disruption to what was a very good game of football and an important part of our pre-season preparation, the pitch invasion was totally unacceptable and has brought shame on everyone connected with Newcastle United.
"We came to play a football match and to provide entertainment for a family audience - instead we witnessed some truly appalling behaviour which damages the reputation of this great club and the vast majority of our true and law-abiding supporters.
"As (managing director) Derek Llambias said yesterday evening, the club will now be taking the strongest possible action against those individuals responsible and that can't happen soon enough. I speak for everyone at Newcastle United when I say I never wish to see those scenes at a football match again."
Llambias was quick to condemn the actions of the supporters, insisting the Magpies would do all they could to identify those involved.
He said: "The club will be seeking to obtain footage of the disorder from Darlington FC and the police and will be taking the strongest possible action against those individuals responsible for the shameful behaviour.
"This behaviour is not typical of the vast majority of our fans, however this incident gives a poor impression of Newcastle United and its loyal supporters."