Germany says Erdogan 'gone too far' with Nazi jibe

Germany angrily warned Turkey on Sunday that President Recep Tayyip Erdogan had gone too far after he accused Chancellor Angela Merkel of using "Nazi measures" in an escalating diplomatic feud.

Turkey and the European Union are locked in an explosive crisis that threatens to jeopardise Ankara's bid to join the bloc, as tensions rise ahead of an April 16 referendum on expanding Erdogan's powers.

The row erupted after authorities in Germany and other EU states refused to allow some Turkish ministers to campaign for a 'yes' vote on their soil, provoking a volcanic response from the Turkish strongman who said the spirit of Nazi Germany was rampant in Europe.

"When we call them Nazis they (Europe) get uncomfortable. They rally together in solidarity. Especially Merkel," Erdogan said in a televised speech on Sunday.

"But you are right now employing Nazi measures," Erdogan said referring to Merkel, pointedly using the informal "you" in Turkish.

"Against who? My Turkish brother citizens in Germany and brother ministers" who planned to hold campaign rallies for a 'yes' vote in the referendum, he said.

Germany's Foreign Minister Sigmar Gabriel branded Erdogan's comments "shocking".

"We are tolerant but we're not stupid," he told the Passauer Neue Presse newspaper. "That's why I have let my Turkish counterpart know very clearly that a boundary has been crossed here."

Julia Kloeckner, the vice-president of Merkel's CDU party, also reacted angrily to the comments.

"Has Mr. Erdogan lost his mind?" she said, telling journalists she was urging the EU to freeze "financial aid amounting to billions of euros" to Turkey.

Home to 1.4 million Turkish voters, Germany hosts the world's largest Turkish diaspora but the partnership between NATO allies Ankara and Berlin has been ripped to shreds by the current crisis.