Sevilla insist midfielder Geoffrey Kondogbia "is not on the market", revealing the club would be offended if another club tried to prise him away this summer.
Kondogbia, 20, has been targeted by Real Madrid and Juventus after a successful season in La Liga and impressive performances in France's Under-20 World Cup winning campaign.
But Sevilla president Jose Maria del Nido has warned Real and Juve not to consider making a move for the youngster.
"Kondogbia is not on the market," Del Nido said. "But whoever wants him has to pay his €20m clause. But please, any team that tries to sign him - don’t. We will consider it an attack.
"I’ve already reached an agreement with [third-party owner] Doyen and Kondogbia will not be leaving this summer."