Turkish president Recep Tayyip Erdogan has drawn criticism from Germany and elsewhere in Europe after accusing Chancellor Angela Merkel of "committing Nazi practices".
Yesterday's accusation was the latest in a string of Turkish comments drawing Nazi parallels with present-day Germany and the Netherlands in a dispute over restrictions on Turkish officials campaigning there in a referendum campaign.
Peter Tauber, the general secretary of Mrs Merkel's conservative party, told N24 television on today that "this is real effrontery toward our chancellor".
However, he added that "we can allow ourselves to be outraged, stamp our feet and perhaps fight back - but the chancellor has to safeguard our country's interests".
The European Parliament's president, Antonio Tajani, wrote on Twitter: "An unacceptable attack by @RT_Erdogan on a democratic country that guarantees all fundamental rights."
Turkey is voting on whether or not to extend Mr Erdogan's powers on April 16, and the president has criticised countries including Germany for not allowing his ministers to campaign on their soil for Turkish nationals' votes.