an independent judiciary, Hahn said in an interview to business daily Handelsblatt.
Finance Minister of the northern state of Schleswig-Holstein Monika Heinold expressed doubts about Fitschen's suitability to continue as co-chairman of Deutsche Bank.
Germany is not a country where criminal investigators will have to stand permanently at the doors of a large bank. Fitschen must understand this, she said.
Carsten Schneider, budget policy spokesman of the opposition Social Democratic Party (SPD), urged Deutsche Bank supervisory board chairman Paul Achleitner to take speedy action to clear up the allegations against the bank.
He should also make sure that the management board fully cooperates with the investigators, Schneider said.
Meanwhile, prominent German judges joined politicians in their criticism of Fitschen.
"It is shocking that a bank chairman believes that he can influence the independence of the judiciary through a telephone call," Christoph Frank, chairman of the Federation of German Judges, told the Frankfurter Allgemeine Zeitung.