Bayern Munich chairman Karl-Heinz Rummenigge has hit out at Borussia Dortmund coach Jurgen Klopp over his recent comments about Matthias Sammer.
Klopp made headlines with his remark that Sammer "should thank God that he's working at Bayern", arguing that the Bavarians' sporting director contributes little or nothing to their success.
But Rummenigge came to Sammer's defence, declaring that the BVB boss had crossed a line.
"At first, I was shocked when I came across that sentence and then I got upset," the former West Germany international was quoted as saying by Welt am Sonntag.
"Matthias won the Champions League with Dortmund during his active career and then the Bundesliga title as a coach.
"Nobody at Bayern would ever be allowed to make such a comment about someone with a past at Bayern and is now a Dortmund employee."
Sammer joined Bayern in the summer of 2012 and saw the club win a historic treble in his first season at the Allianz Arena.