Bayern Munich CEO Karl-Heinz Rummenigge has said they will not allow any of their key stars to leave amid speculation linking Real Madrid with Robert Lewandowski and David Alaba.
Madrid have been linked with Poland striker Lewandowski and Austria star Alaba for several months and representatives of both players have recently fuelled the rumours.
One of Lewandowski's agents said last month that talks with the Spanish side had taken place, while Alaba's father said last week that he was "proud" that Madrid continued to show interest in his son.
Bayern have insisted on more than one occasion that Lewandowski, 27, will stay and Rummenigge has stressed that they will not entertain bids for any players unless they wish to sell.
"We have closed the door," he told Sport Bild. "No player will leave Bayern against our will."
Bayern had appeared to be facing a losing battle to keep Franck Ribery at the club for several years toward the end of the last decade after he expressed a desire to play in Spain, but the French star ultimately stayed in Munich.
The German champions have been proactive in the market ahead of Carlo Ancelotti's first season in charge, bringing in Mats Hummels and Renato Sanches, while they have allowed Sebastian Rode to join Borussia Dortmund.
ESPN FC's Germany correspondent, Stephan Uersfeld, contributed to this report.