Dortmund chief-executive Hans-Joachim Watzke has declared clubs like Manchester City should be thrown out of European competition if their owners "pump crazy money" into their teams with "back-door" sponsorship deals.
The 53-year-old stated the Bundesliga champions will not sacrifice their financial model in favour of an overseas benefactor akin to Sheikh Mansour at PremierLeague champions City.
And Watzke warned Uefa's new Financial Fair Play model is doomed to failure unless they investigate the sponsorship deals clubs are making as they attempt to avoid new financial regulations.