Sir Alex Ferguson has written to Manchester United supporters urging them to behave at away matches after it was revealed that their ticket allocation for the upcoming trip to Liverpool on October 15 had been cut.
The Red Devils usual allocation of 3,000 tickets for the match on Merseyside has been reduced to 1,960 after recent incidents involving their fans.
Last month 14 men were charged following unrest at Elland Road during United and Leeds' Carling Cup tie.
"Despite intense lobbying by the club on your behalf, there will only be just over 1,900 United fans at Anfield," wrote Ferguson. "We can't allow this situation to continue. I've said many times that your support is a vital part of our success and, trust me, the players do notice when your numbers are cut."
United are currently top of the Premier League on goal difference, ahead of local rivals Manchester City.