Benedict, the first German pope in 500 years, has faced a fierce backlash from his home country for reversing the excommunication of a bishop who has questioned whether the Nazis systematically killed 6 million Jews during the Holocaust.

Several leading German Catholics have joined in the criticism in recent days, openly wondering whether Benedict and the Vatican knew what they were doing in rehabilitating the bishop, Richard Williamson, who has not backed away from his comments on the Holocaust.

In a radio interview Monday, Cardinal Karl Lehmann, the bishop of Mainz, said Benedict’s order was “a disaster for all Holocaust survivors” and called on the Vatican to apologize. Werner Thissen, the archbishop of Hamburg, called the case “dreadful” and accused Benedict’s advisers of bungling the episode.

The Vatican has distanced itself from Williamson’s views. Last Wednesday, Benedict declared his “full and indisputable solidarity” with Jews and warned against the dangers of denying the Holocaust.

But the pope’s comments only fanned concerns among many Germans that he was not taking the situation seriously enough.

It is a crime in Germany to deny the existence of the Holocaust. Merkel, the daughter of a Lutheran pastor, said the German pope has a special responsibility to speak out more clearly on the subject.

“The pope and the Vatican should clarify unambiguously that there can be no denial and that there must be positive relations with the Jewish community overall,” Merkel told reporters in Berlin. She said the Vatican’s efforts to explain itself were “not yet sufficient.”