Germany on Monday dismissed as unacceptable an accusation by Turkish President Tayyip Erdogan that Chancellor Angela Merkel is "applying Nazi methods" against Turks and Turkish officials in Germany.

"Nazi comparisons are unacceptable in any form," a German government spokeswoman said, adding that it was up to Turkey to tone down its rhetoric and avert damage to relations between the two countries.

Erdogan said in a speech in Istanbul on Sunday: "Merkel, now you're applying Nazi methods. Against my brothers who live in Germany, and against my ministers and lawmakers who visit there. Would this suit the ethics of politics? Your mission is not to support terrorist organizations, but to extradite them."