Bayern Munich president Uli Hoeness has hit out at Barcelona's efforts to sign Ousmane Dembele from Borussia Dortmund.
The Catalans have had an offer reportedly worth EUR100m rejected by Dortmund but are believed to still be eager to sign the 20-year-old as a replacement for Neymar, who left for Paris Saint-Germain in a world-record EUR222m deal.
Dembele has been suspended by Dortmund after failing to report for training and is thought not to have been in contact with the club for the past week.
Team-mate Gonzalo Castro admitted on Friday that the squad have been stunned by Dembele's behaviour, although he stressed that "we don't know who is behind his actions or who leads him".
Bayern have signed a number of players from Dortmund in recent years, including Mario Gotze, Robert Lewandowski and Mats Hummels, but Hoeness has described Barca's attempts to bring Dembele to Camp Nou as "the lowest class".
Speaking on Eurosport ahead of Bayern's opening Bundesliga win over Bayer Leverkusen on Friday, he said: "If Barcelona are behind it, then I have no respect for the club.
"Forcing a player to break a contract is the lowest class."
Barca general manager Pep Segura suggested this week that deals for Dembele and Philippe Coutinho were close, although those claims were dismissed by Dortmund and Liverpool.
Ernesto Valverde's side begin their Liga campaign against Real Betis on Sunday.