Mick Everett, Charlton FC's Head of Operations, said:
"The club was shocked to hear of the rowdy, intimidating behaviour, and the chanting of racist songs on a train by a handful of our supporters.
"Their actions are totally condemned by everyone at the club and indeed, I am sure, by Charlton supporters everywhere.
"Although this isolated incident does not reflect on the overwhelming majority of our fans, these arrests are a kick in the teeth to everyone associated with the club, who have put so much effort into our campaign over the years.
"The club will now look to impose additional appropriate sanctions on those involved."
More top news
Here is a timeline of some of the key events in the debate over expansion of airport capacity.
More than 700 households were today bracing themselves for a government decision which could see their homes bulldozed.
Dozens of cats bear the hallmarks of the cat murderer who is suspected to have killed upwards of 100 cats, mostly in the south London area.