Austrian Chancellor Christian Kern's comments spark angry response from Ankara
Negotiations with Turkey in its quest to become a member of EU are a "fiction", according to the Austrian Chancellor.
Using language which could deepen the rift between the EU and Turkey, Christian Kern told the Austrian newspaper Die Presse it was important to "face the reality: the accession negotiations are currently no more than a fiction".
Mr Kern suggested he would consult other EU leaders about ending all discussion of a possible Turkish membership.
His words prompted an angry response from Turkey's Europe Affairs Minister, who said they came close to the rhetoric of the far right.
"It's disturbing that his statements are similar to those of the far right ... Criticism is surely a democratic right but there has to be a difference between criticising Turkey and being against Turkey," Omer Celik told reporters in Ankara.
Mr Kern said Turkey's illegibility for membership was not only as a consequence of President Recep Tayyip Erdogan's hard-line crackdown following the coup attempt, but also because of the clear economic disparities between EU countries and Turkey.
European Commission president Jean-Claude Juncker has appeared to distance himself from the remarks, telling German television he does not think it would be helpful to end the negotiations.
If Turkey was to join the EU it would have to sign up to the four fundamental pillars of the Union - free movement of goods, services, capital and people - which Mr Kern warned would create massive economic distortions not acceptable in Europe.
The prospect of Turkey joining the EU was a key issue in the UK referendum, with the Vote Leave campaign presenting it as a certainty.
Many in the Remain campaign insisted there was no prospect of Turkey becoming an EU member for many decades, if at all.
The Austria-Turkey row is only the beginning of what's expected to be a particularly bitter disagreement between the EU and Turkey, which will have big implications when it comes to a head in the next few months.
In March, at the height of the continent's migration crisis, the EU reluctantly agreed to re-energise talks with Turkey about its future EU membership, as well as accelerate visa liberalisation for Turkish nationals wanting to travel to the EU.
In return, Turkey agreed to help Europe deal with its migration crisis by taking back "all new irregular migrants" and stepping up coastal border patrols.
The deal was done at a time when European leaders were backed into a corner with the migrant crisis out of control: the only way to stem the flow of migrants into Europe through Greece was to strike a deal with Turkey who had the power to stop the migrants; and the only way to get Turkey on board was to offer them an EU membership carrot.
But the deal is now showing signs that it could be about to fall apart. The Austrian Chancellor's comments add to the concern.
In return for visa-free travel for its 79 million people within the Schengen Zone of the EU (which doesn't include the UK), Turkey was required to meet 72 criteria.
These included small issues like bringing Turkish passports up to EU standards.
But it also included bigger and more difficult issues which Turkey has failed to deliver on, including changing its definition of which groups are classed as terrorists.
The visa liberalisation package - visa-free travel for a three month period - was due to come into effect in June.
That deadline has now passed and a new one is set for October.
Turkey has threatened that if it doesn't get visa free travel for its citizens by then, it will drop its side of the bargain.
EU leaders have said they will not be blackmailed, but they are presented with a clear dilemma.
Either they risk allowing the resumption in the flow of thousands of Iraqi, Syrian and Afghan refugees and migrants into Greece from Turkey, or they grant visa-free travel to Turkey despite the government in Ankara failing to meet fundamental criteria and displaying increasingly autocratic signals - especially since the attempted coup - which put it well out of line with European values.
There is one silver lining for EU leaders. The fall in the number of migrants and refugees coming to Europe via Turkey is, in significant part, a result of Turkish cooperation following the deal.
But the closure of European borders along the migrant route has also discouraged others from making the journey.
EU leaders could gamble; reject Turkish demands for visa liberalisation, let the deal collapse and then hope that border closures continue to stem the flow.