Turkey told the Netherlands on Sunday that it would retaliate in the “harshest ways” after Turkish ministers were barred from speaking in Rotterdam, as a row over Ankara’s political campaigning among Turkish immigrants escalated.

Foreign Minister Mevlut Cavusoglu said the Netherlands was the “capital of fascism” as it joined other European countries in stopping Turkish politicians holding rallies due to fears that tensions in Turkey might spill over into their communities.

The Dutch government barred Cavusoglu from flying to Rotterdam on Saturday and later stopped Family Minister Fatma Betul Sayan Kaya from entering the Turkish consulate there, before escorting her out of the country to Germany.

Dutch police used dogs and water cannon on Sunday to disperse hundreds of protesters waving Turkish flags outside the consulate in Rotterdam. Some threw bottles and stones and several demonstrators were beaten by police with batons, a Reuters witness said. Mounted police officers charged the crowd.

The Dutch government – set to lose about half its seats in elections this week, according to polls, as the anti-Islam party of Geert Wilders makes strong gains – said the ministers’ visits were undesirable and it would not cooperate in their campaigning in the Netherlands.

“If you can sacrifice Turkish-Dutch relations for an election on Wednesday, you will pay the price,” Recep Tayyip Erdogan said in a speech at an awards ceremony in Istanbul.

“I thought Nazism was dead, but I was wrong. Nazism is still widespread in the West,” he said. “The West has shown its true face.”

Speaking to reporters before a public appearance in the northeastern French city of Metz, Cavusoglu said Turkey would continue to act against the Netherlands until it apologizes.

Dutch Prime Minister Mark Rutte said he would do everything to “de-escalate” the confrontation, which he described as the worst the Netherlands had experienced for years.

But he said the idea of apologizing was “bizarre”.

“This is a man who yesterday made us out for fascists and a country of Nazis. I’m going to de-escalate, but not by offering apologies. Are you nuts?” he told a morning talk show.

France calls for calm

In a statement issued early on Sunday, Turkish Prime Minister Binali Yildirim said Turkey would retaliate in the “harshest ways”.

The row risked spreading on Sunday as Denmark’s Prime Minister Lars Lokke Rasmussen proposed postponing a planned visit by Yildirim this month due to the dispute.

The French foreign ministry urged calm and said there had been no reason to prohibit a meeting in France between Cavusoglu and a local Turkish association.

Supporting Rutte’s decision to ban the visits, the Dutch government said there was a risk of Turkish political divisions flowing over into its own Turkish minority, which has both pro- and anti-Erdogan camps.

The diplomatic row comes in the run-up to next week’s Dutch election in which the mainstream parties are under strong pressure from Wilders’ Party for Freedom (PVV).

After Turkey’s family minister was escorted into Germany, Wilders tweeted: “go away and never come back”.

Experts said it was too early to tell how events in Rotterdam might affect the election, though the two front runners have both campaigned on tough-on-immigration themes.

“If there is any impact, however, it is likely that Geert Wilders and his PVV Party will profit most,” said Leiden Professor Joop van Holsteijn in an email to Reuters.

The Dutch government cited public order and security worries in withdrawing landing rights for Cavusoglu’s flight and Turkey fired back saying the Dutch ambassador to Ankara should not return from leave “for some time”.

Hundreds of protesters gathered outside the Dutch embassy in Ankara and consulate in Istanbul. Police sealed off both sites.

“Capital of Fascism”

Cavusoglu kept up his harsh language during his visit to the northeastern French city of Metz.

“The Netherlands, the so-called capital of democracy, and I say this in quotation marks because they are actually the capital of fascism…,” he said in a speech on Sunday.

Erdogan is looking to the large number of Turks living in Europe, especially in Germany and the Netherlands, to help secure victory next month in a referendum that would give the presidency sweeping new powers.

German Chancellor Angela Merkel has said she will do all she can to prevent Turkey’s domestic tensions spreading onto German territory. Austria and Switzerland have also canceled Turkish rallies due to the escalating dispute.

A senior member of her conservative bloc in parliament, Hans Michelbach, demanded on Sunday that the European Union stop aid to Turkey and ruled out any hopes that it would join the bloc.

“There is no prospect of entry in the long run. Turkey is getting further and further away from the European Union. Support programmes (that it gets as an EU candidate) are therefore a waste of taxpayers’ money,” he said in a statement.

“It is time that the EU stops performing like a diplomatic paper tiger toward Ankara. Europe must not be led by the nose round the Turkish election arena.”

European Parliament Vice President Alexander Graff Lambsdorff demanded a ban on Turkish ministers campaigning in the EU.

“The European Union should agree on a line that Turkish ministers are not allowed to campaign in the EU,” he said.

“The Dutch are showing how it is done, the German government pussyfoots around … in that way Turkey can try to play one country off the other,” he told Die Welt newspaper.

Erdogan’s spokesman said the Netherlands had bowed to anti-Islam sentiment.

“Shame on the Dutch government for succumbing to anti-Islam racists and fascists, and damaging long-standing Turkey-NL relations,” spokesman Ibrahim Kalin tweeted.

In a sign the row might spread further, the owner of a venue in Sweden where a senior official from Turkey’s ruling party had been due to hold a rally on Sunday canceled the rental contract, Turkey’s private Dogan news agency reported.

The news agency said the owner had not given a reason for the decision.

Cavusoglu also decided against traveling to Switzerland for an event on Sunday after failing to find a suitable venue. Zurich’s security authorities had unsuccessfully lobbied the federal government in Bern to ban Cavusoglu’s appearance.