Newcastle United have insisted that the behaviour of a certain number of travelling supporters last weekend is "wholly unacceptable".
A swarm of Magpies fans were accused of disrupting an amateur match in Wigan ahead of their side's 2-1 defeat at the DW Stadium.
The supporters are said to have stormed the pitch, dropped their trousers, and attempted to pull down the goal nets during a game between the Wigan Cosmos and AFC Leigh Centurions.
A statement on the Magpies' official website said: "Newcastle United are very disappointed with the behaviour of a minority of its fans who were involved in the vandalism of equipment belonging to Wigan Cosmos Football Club and pitch incursions during their game against AFC Leigh Centurions on Sunday, March 17 which caused the match to be stopped.
"Our travelling fans have a very good reputation, but the actions of a minority on this occasion were wholly unacceptable. Football, at all levels of the game, deserves the same degree of respect whether it is played in the Premier League or at the grassroots level.
"We were sorry to learn that this South Lancashire Counties Premier Division game was disrupted in this manner and we would urge anyone who witnessed this incident to contact Greater Manchester Police. The club will be contacting Wigan Cosmos to arrange to reimburse them for the damage."
Meanwhile, the North-East outfit have confirmed that Massadio Haidara could return to fitness within 10 days.
