BERLIN (Reuters) - The leader of Germany’s Turkish community on Monday accused President Tayyip Erdogan of damaging ties between the two NATO allies by likening bans on political rallies by Turks in Germany to “fascist actions” reminiscent of Nazi times.

Turkish President Tayyip Erdogan makes a speech during a Women's Day rally in Istanbul, Turkey, March 5, 2017. The slogan in the background reads that: "Yes! If there is woman, there is democracy". REUTERS/Murad Sezer

Erdogan’s comments on Sunday have further soured relations as public outrage in Germany mounts over Turkey’s arrest a week ago of Turkish-German journalist Deniz Yucel.

“Erdogan went a step too far. Germany should not sink to his level,” Gokay Sofuoglu, chairman of the Turkish Community in Germany, which groups 270 member organizations, told Reuters.

He said the comments could harm bilateral ties and were exacerbating long-simmering tensions within the community of about 3 million people of Turkish background in Germany.

Sofuoglu said he had talked to police after receiving messages accusing him of being a “terrorist” because of his criticism of Erdogan and of a coming referendum to expand the powers of the Turkish presidency.

But he urged authorities not to ban Erdogan or other Turkish politicians from Germany, saying it was important to set a positive example and preserve rights to freedom of expression.

Two German towns last week canceled political rallies at which Turkish ministers had hoped to drum up support for a “Yes” vote in the April 16 referendum.

An estimated 1.5 million Turkish citizens living in Germany are eligible to vote in the poll, making them one of the largest constituencies outside Turkish cities like Istanbul.

German chancellor Angela Merkel insists the rallies were canceled by the local authorities for security reasons and that federal officials were not involved.

German politicians continued to react with shock and anger to Erdogan’s comments on Monday, with many demanding an immediate apology.

“Such accusations are absolutely unacceptable,” Merkel’s chief of staff Peter Altmaier told German broadcaster ARD, in the chancellery’s first comments since Erdogan’s latest salvo.

Altmaier said Germany valued freedom of expression and would not prevent appearances by Turkish politicians, but that such speeches should respect “legal boundaries and existing law”.

He said Merkel and Foreign Minister Sigmar Gabriel would address the meaning of the latest events with Ankara, as well as Germany’s demand that Turkey free Yucel, whom Erdogan says is a “German agent” and a member of an armed Kurdish militant group.

A source in Germany’s foreign ministry told Reuters on Friday those accusations were “absurd”.

Gabriel, who is due to meet Turkish Foreign Minister Mevlut Cavusoglu in Berlin on Wednesday, told reporters in Brussels: “The relationship is clearly strained and it is our responsibility to normalize it.”