Germany on Monday branded as "unacceptable" Turkish President Recep Tayyip Erdogan's charge that Chancellor Angela Merkel was using "Nazi measures", but signalled it wanted to avoid escalating the feud.
Turkey and the European Union -- especially Germany with its large Turkish diaspora -- are locked in a bitter dispute as tensions rise ahead of an April 16 referendum on expanding Erdogan's powers.
Erdogan made the remark about Merkel at the weekend after the authorities in Germany had refused to allow several Turkish ministers to campaign for a 'yes' vote on their soil.
Merkel's spokeswoman Ulrike Demmer said Monday: "The government is watching this very closely, and we maintain that Nazi comparisons are unacceptable in any form."
She refrained from further comment, however, while a foreign ministry spokesman indicated that Berlin had no interest in entering a spiral of mutual provocations designed to boost support for Erdogan among Turkish overseas voters.
"Who would really benefit from it if we paid back in kind, if we answered using the same language as the Turkish president," said the ministry spokesman, Martin Schaefer.
"It benefits mostly the Turkish president who... with threats, insults and more is seeking majorities of Turkish citizens in Turkey and also... in Germany for the constitutional referendum of April 16."
To hit back with strong verbal retaliation would mean falling for Erdogan's tactic, Schaefer said, stressing that Germany is "a strong, democratic country" that could handle such insults.
"We are not defenceless or stupid or naive and, if pushed too far, the government will react."
Demmer said it was "up to the Turkish government to moderate its rhetoric and prevent lasting damage to bilateral relations".