Bayern Munich have warned that any fans caught abusing new signing Manuel Neuer will be effectively banned.
The former Schalke shot-stopper was given a cold welcome by some of the 2,500 fans that watched Bayern's 15-0 friendly win against Trentino on the shores of Lake Garda, Italy.
Last Saturday, Bayern's bosses held a round-table discussion with fans' groups to urge them not to attack the keeper, however, one banner displayed in the friendly read: "You can save as many balls as you like. We will never accept you in our shirt."
Bayern will not tolerate those who gave Neuer a hostile reception on Wednesday and are saying the section of fans who abused the keeper are no longer welcome at the Allianz Arena.
"As a result of the round-table talks, it was agreed that Manuel be seen by all fans as a member of the Bayern Munich team, that he will be treated with respect and will not be subjected to insults," read Bayern's statement.
"At (Wednesday's) game against Trentino, a small group from the ultra scene broke this agreement.
"Bayern Munich distanced themselves from both the banner displayed against Manuel Neuer, as well as those who were part of this small group.
"We also wish to make it known that this was a very small group that is not registered with Bayern.
"Due to the events in Arco (Trentino), the people in this group are now 'persona non grata' with Bayern Munich."