Turkish President Recep Tayyip Erdogan blasted Germany on Sunday for blocking rallies in support of him ahead of an April vote on boosting his powers, likening it to Nazi practices.
The attack came a day after German Chancellor called Turkish Prime Minister Binali Yildirim to try to defuse the row, which is severely straining ties between the NATO allies.
A number of local authorities in Germany have banned rallies ahead of an April 16 referendum on whether to approve changes to the constitution.
"Germany, you are not even close to democracy," Erdogan told a women's rally in Istanbul. "Your practices are not different from the Nazi practices of the past," he said.
"I thought it's been a long time since Germany left (Nazi practices). We are mistaken," he said.
Several German towns prevented appearances by Erdogan's ministers last week, citing security and safety concerns.
The cancellations have infuriated the Turkish government, which accused Berlin of working against the "Yes" campaign in the referendum and summoned the German ambassador to the foreign ministry in protest.
Chancellor Merkel called the Turkish premier on Saturday and the two countries' foreign ministers are set to meet later this week.
Germany is home to the biggest population of Turks outside Turkey with around three million in the country of Turkish origin, the legacy of a massive "guest worker" programme in the 1960s-70s.
- Austria urges EU ban -
Erdogan's ruling Justice and Development Party (AKP) says the changes would bring political stability, but the vote is widely seen as a referendum on Erdogan himself because the proposed plan could see him stay in power until 2029.
Opponents however say the changes that would grant sweeping new powers to the head of state would make parliament dysfunctional and promote a one-man model.
Austrian Chancellor Christian Kern said Sunday that Turkish politicians should be banned from political campaigning across the European Union.
"A collective EU response to prevent such campaign events would make sense so that individual countries like Germany where appearances are forbidden don't end up being pressured by Turkey," Kern told German newspaper Welt am Sonntag.
Turkish rallies have also come under scrutiny in the Netherlands where Dutch Prime Minister Mark Rutte said a planned pro-Erdogan rally in Rotterdam on March 11 would be "undesirable".
Erdogan on Sunday said other EU member states with significant Turkish communities were likely to follow the suit.
"The Netherlands acted similarly and maybe others will follow. Don't matter wherever you come from," he said. "If you say democracy, you must give its due."
Tensions with Germany, a European Union heavyweight, are simmering especially after the failed military coup bid in July that sought to unseat Erdogan.
Ankara has launched a vast crackdown in the aftermath of the failed putsch, which has seen more than 100,000 people arrested, dismissed or sacked for alleged links to the plotters or to Kurdish militants.
Berlin has criticised the formal arrest of Deniz Yucel, 43-year-old Turkish-German dual national correspondent for Germany's Die Welt newspaper charged by an Istanbul court with spreading terrorist propaganda and inciting hatred.
Erdogan on Friday said that the journalist had been sheltered at the German consulate for a month before the detention, claiming that he was a "German agent."
On Sunday he lashed out at Berlin repeatedly.
"You will lecture us about democracy and then you will not let this country's ministers speak there," said an angry Erdogan, adding that Germany was not "respecting opinion and thought".
"We no longer want to see the Nazi world. We don't want to see the practices of those fascist regimes."