Borussia Dortmund CEO Hans-Joachim Watzke has told Sport Bild the club remains "calm" over contract negotiations with Marco Reus but said: "It's his decision alone."
The row between Dortmund and Bayern Munich continues to summer ahead of Wednesday's German Super Cup between the two sides at the Westfalenstadion.
Karl-Heinz Rummenigge has provoked tensions by repeatedly discussing Reus' release clause, which he claimed in an interview with ESPN FC would allow the Germany international to leave for 25 million euros next summer. The Bayern CEO said Dortmund would find it "difficult" to renegotiate his contract and remove the clause and that there would be interest from an array of top clubs.
Despite Dortmund's anger, Bayern sporting director Matthias Sammer rejected criticism, insisting the German champions "will not allow anyone to forbid us to speak."
Watzke -- who has said he will not attend the traditional pre-Super Cup lunch with German league officials, and representatives from Dortmund and Bayern -- told Sport Bild on Wednesday that he knows "no other case in which officials from another company continuously discuss internal affairs of a competitor."
He demanded that BVB be treated with respect, adding: "No other Bundesliga club does it. Nobody in Germany speculated about Toni Kroos' transfer to Real Madrid. That's none of our business -- and I expect this respect to be shown towards us and other clubs as well."
Sport Bild reports that Dortmund, who have been powerless to prevent Mario Gotze and Robert Lewandowski moving to Bayern in recent times, are prepared to offer Reus a new contract worth six million euros a year, but anonymous sources told the publication that the offer is insufficient.
Even so, Dortmund have not given up hope of agreeing a new deal with Reus, who returned to his hometown club from Borussia Monchengladbach in 2012.
On Sunday, Reus was named vice-club captain, and Watzke said the 25-year-old could be given more and more responsibility in the coming years.
"From my point of view, it's a special opportunity to make your mark on a whole era of a club as Dortmund-born player," Watzke said.
"It would give you an extraordinary status at the club, and maybe give you a tie to the club in a high-ranking position for the rest of your life. I could imagine that for Marco. We remain calm, and put no pressure on him. It's his decision alone."
Suddeutsche Zeitung reported on Wednesday that Reus had turned down an approach from Bayern this summer and that that might have led to Rummenigge's recent statements.
Pep Guardiola, though, told reporters on Tuesday that he does not need Reus as he already has eight attacking players at the club, while the player's agent, Dirk Hebel, told Bild that there has not been any contact with Bayern.
Reus, who has returned to team training following an ankle injury that prevented him taking part at the World Cup, has remained silent over his future throughout the summer.