Crawley Town FC have spoken of their shock after children were seen among those throwing missiles onto the pitch during Saturday's game (16 September).
Flares were thrown in the direction of Tranmere Rovers FC goalkeeper at the Broadfield Stadium.
One young supporter with asthma began to have an attack when the first device was thrown.
In a statement, the club said: "Crawley Town Football Club unequivocally condemns the behaviour from select individuals in the South Terrace during today’s fixture against Tranmere Rovers.
"Upon Crawley equalising in the 61st minute, a large group of 'supporters' proceeded to launch a number of missiles in the direction of the Tranmere Rovers goalkeeper. Behaviour like this is unfathomable and will not be tolerated. The club have already launched an internal investigation and anyone found to be throwing missiles of any kind onto the field of play will be indefinitely banned from the Broadfield Stadium and may face wider football bans.
"Owing to the behaviour of these supporters, there was a very real possibility of the game being abandoned at 1-1, a scenario that was only avoided owing to the response from the club security team. First team players and staff have also lodged their displeasure at these scenes owing to the stoppage in play that ensued as a result of the fans behaviour which lost the team momentum when the impetus was with them.
"The club will now likely receive a sanction from the FA which will provide significant financial stress for the club - something that could be better spent to ensure the continued progress of the team. Other potential sanctions include stand and stadium closures as well as points deductions. Unfortunately owing to the continual bad behaviour of a select group of fans, these are now very real sanctions that the club could face in the coming weeks. The support this season home and away has largely been superb, however it is exceedingly disappointing, and now concerning that these select groups, who do not represent the wider fan base, continue to let the club down in this way.
"Crawley Town Football Club wishes to formally apologise to Luke McGee and Tranmere Rovers for the abuse suffered this afternoon and will be making no further comment at this stage."
Sam Jordan, from the Crawley Town Supporters' Alliance, said: "It's the first time it ever happened. It's not acceptable, not what we want at Crawley Town FC. Hopefully it doesn't happen again."
The club could face sanctions by the FA.
Simon said: "There could be certain parts of the ground that are shutdown or even we can't play with fans so that's the worst case scenario. It needs to stop really. We don't want that to happen at our football club.
"Come and enjoy the game, get behind the players, make sure the atmosphere is good but don't throw things on the pitch. That's not acceptable. It's not funny, it's not a good idea and it needs to stop as it's going the impact the players on the pitch ultimately. If we get fined, we won't be able to cheer for the team and that's not good for the football club."
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