The Turkish foreign ministry has rejected a call by top EU officials to show restraint in a row with the Netherlands over political campaigning.
It described as “worthless” an appeal by EU foreign policy chief Federica Mogherini and EU Enlargement Commissioner Johannes Hahn.
The row erupted after the Dutch barred Turkish ministers from campaigning among expatriates for a referendum.
It comes before one of the most closely fought Dutch elections in years.
The referendum would controversially boost the powers of Turkish President Recep Tayyip Erdogan.
In response to the Dutch move, Turkey barred the Dutch ambassador from returning to Ankara and suspended high-level political talks, while Mr Erdogan accused the Dutch of using Nazi tactics.
The Dutch government cited “risks to public order and security” as reasons for blocking the Turkish rallies.
Turkey’s foreign ministry said it was “grave” of the EU to stand by the Netherlands.
On Monday, Ms Mogherini and Mr Hahn had called on Turkey to “refrain from excessive statements and actions that risk further exacerbating the situation”.
However, responding to the diplomatic sanctions announced by Turkey, Dutch Prime Minister Mark Rutte said they were “not too bad”.
Why did the Dutch ban the Turkish rallies?
Rallies were called to encourage Turkey’s large expatriate communities in the EU to vote Yes in a referendum on 16 April on expanding the president’s powers.
Some 5.5 million Turks live outside the country, including an estimated 400,000 in the Netherlands.
The Dutch authorities barred two Turkish cabinet ministers from addressing crowds in the city of Rotterdam, with Minister of Family Affairs Fatma Betul Sayan Kaya escorted to the German border after entering the Netherlands by land.
Prime Minister Rutte said the city authorities had feared an armed clash between Ms Kaya’s security detail and local police.
While the Dutch position was that the rallies posed a threat to public order, the EU has made very clear its unease over the Turkish referendum itself.
In their statement on Monday, Ms Mogherini and Mr Hahn voiced concern that it could lead to an “excessive concentration of powers in one office”.
How high are passions in this row?
Mr Erdogan likened the Netherlands to a “banana republic”. The country, which has the sixth largest economy in the EU, is the biggest source of foreign investment in Turkey.
In a speech on Tuesday, he accused the Dutch of “massacring” Muslim men and boys at Srebrenica, during the Bosnian civil war in 1995, saying it was evidence of their “rotten character”.
Dutch UN peacekeepers failed to protect Muslim civilians sheltering from Bosnian Serb forces. The UN tribunal investigating the massacre of 7,000 men and boys prosecuted Bosnian Serbs for the actual killings.
The Dutch prime minister condemned Mr Erdogan’s remarks as a “vile falsification of history”.
Earlier, he said a comment by Mr Erdogan that the Dutch were “Nazi remnants” was “unacceptable”, and demanded an apology.
The Netherlands was invaded by Nazi Germany in 1940 and occupied right up until the final days of World War Two in Europe, in May 1945. Rotterdam was devastated by German bombing during the invasion.
How is this affecting the Dutch election?
Voters in the Netherlands go to the polls on Wednesday for a general election dominated by concerns about immigration and Islamic radicalism.
The anti-Islam Freedom Party of Geert Wilders has long been seen as benefiting from the anti-establishment sentiment which fuelled the victories of Brexit campaigners in the UK and Donald Trump in the US last year.
However, Mr Rutte’s handling of the Turkish rallies may benefit his centre-right People’s Party for Freedom and Democracy (VVD), which governs in coalition with the Labour Party.
The Peilingwijzer poll of opinion polls suggests the VVD will win 17% of the vote to 14% for the Freedom Party.
Party leaders are due to hold a final debate on Tuesday evening.
Could there be wider repercussions?
Mr Erdogan warned on Tuesday of other, unspecified measures Turkey might take against the Netherlands.
Relations between the EU and Turkey, a predominantly Muslim country regarded as crucial to tackling Europe’s migrant crisis, have long been strained.
Turkish officials have suggested reconsidering part of the deal with the EU to stem the flow of undocumented migrants.
The number of migrants reaching Greece by sea dropped sharply after the deal was reached in March of last year.
Turkey is also a candidate to join the EU but negotiations have made little headway over the last decade.
As a Nato state bordering Syria, it is also a vital partner in the campaign to fight so-called Islamic State.
A note on terminology: The BBC uses the term migrant to refer to all people on the move who have yet to complete the legal process of claiming asylum. This group includes people fleeing war-torn countries such as Syria, who are likely to be granted refugee status, as well as people who are seeking jobs and better lives, who governments are likely to rule are economic migrants.