Bayern Munich have warned that they will report Real Madrid to FIFA if they continue a very public approach to trying to sign French ace Franck Ribery.
The German giants are adamant that forward Ribery is not for sale at any price and general manager Uli Hoeness has issued a blunt warning to their Spanish rivals.
He told AS: "Madrid have lost respect. If this continues we will report them to FIFA.
"People such as Emilio Butragueno or Zinedine Zidane are speaking out and they should not be doing so, because they are talking about a player who has a contract with us.
"The only legitimate people to talk are (president) Florentino Perez and (sporting director) Jorge Valdano.
"We will report the Madrid club to FIFA if they continue like this. We haven't done so yet because of respect for Butragueno and (international affairs spokesman) Jose Luis Lopez Serrano."
Meanwhile, Hoeness has revealed that Franck Ribery is tempted to join suitors Real, but has reiterated his recent claim that the France star is not for sale.
"I can fully see Franck's viewpoint," he said amid reports of Real being ready to offer Ribery a weekly wage of 150,000 euros.
"Franck is 26 years old and it's quite natural that he would be tempted by all this.
"I would be interested to see how the other players at the club would react when confronted by something like that.
"I doubt that they would all happily continue being a Bayern Munich player.
"But Franck Ribery will remain at Bayern Munich. There is no doubt."
Elsewhere, Borussia Dortmund striker Alexander Frei is hoping to complete a return to his native Switzerland with FC Basel.
The 30-year-old international has spent two seasons in the Bundesliga, but is hoping to return home ahead of the start of the new campaign.
"There is interest on both sides in Alex coming to Basel," revealed the Swiss club's vice-president Bernhard Heusler.
"However, there are still many obstacles which must be removed. But obstacles are there to be overcome."
Frei, who spent two years with Basel at the beginning of his career, added: "A return to Basel would be a dream for me."