Turkey's top diplomat escalated on Friday a war of words with Austria, calling it the "capital of radical racism" after Vienna urged an end to Ankara's EU membership talks.

"Racism is an enemy of human rights and humanitarian values and the Austrian chancellor should first look at his own country," Foreign Minister Mevlut Cavusoglu told TGRT news channel.

"Austria is the capital of radical racism," he said.

Cavusoglu was reacting to comments made by Austrian Chancellor Christian Kern who said Turkey was unfit to join the European Union in the aftermath of the July 15 attempted coup by a rogue faction within the military.

"We have to face reality: the membership negotiations are currently no more than fiction," Kern told the Die Presse newspaper in comments published on Thursday.

Cavusoglu blasted Kern's "ugly" comments.

Turkey has already faced much criticism and delay in its bid to join the EU which could face further issues after President Recep Tayyip Erdogan's suggestion last month that he may reintroduce the death penalty following the failed putsch.

Cavusoglu said he rejected all of Kern's criticisms of Turkey, which included the statement that Ankara's democratic standards were "far from sufficient to justify its accession".

Reacting on Twitter soon after Cavusoglu made those comments, Austrian Foreign Minister Sebastian Kurz urged his counterpart to "exercise restraint".

"I urge the foreign minister to exercise restraint and sharply reject his criticism. Turkey needs to moderate its choice of words and actions," he said in German.

On Thursday, European Commission President Jean-Claude Juncker rejected Vienna's call to end talks over Turkish accession, saying it would be a "serious foreign policy mistake".

"I don't think it would be helpful if we were to unilaterally end negotiations with Turkey," Juncker told German public broadcaster ARD.

Turkey's EU membership bid dates back to 1963, with its formal application made in 1987 and negotiations starting in 2005.