The European Union and Turkey are arguing over whether Ankara's bid to join the EU should continue.
Turkish President Recep Tayyip Erdogan said the EU would not be able to reach the "final point" and end its ties with Turkey out of fears of jeopardising a deal to curb the flow of migrants from Africa and the Middle East to Europe.
Hours later, in Brussels, EU enlargement commissioner Johannes Hahn said "it is time Ankara tells us what they really want", in the wake of a report assessing Turkey's status as a candidate for membership that highlighted what the EU saw as backsliding on essential human rights and rule of law standards.
The report came after Turkey's clampdown on media freedoms and the arrests of 10 pro-Kurdish legislators.
"These various actions, including considerations of reintroducing the death penalty, seem to be increasingly incompatible with Turkey's official desire to become a member of the European Union," Mr Hahn said.
"In its own interest, Turkey urgently needs to stop moving away from the EU," Mr Hahn said.
In the escalating stand-off on Turkey's protracted membership bid, Mr Erdogan rose to the challenge.
"They say unabashedly and shamelessly that the EU should review its negotiations with Turkey," Mr Erdogan told a business group in Istanbul. "You are late, go and review them as soon as you can. But don't just review them - go and make your final decision."
The Turkish leader added: "You know those 3 million refugees in Turkey? They say there is a problem. What if the negotiations end and they open the gates, where would we put those 3 million refugees? That is their worry. That is why they cannot come to the end point."
Turkish foreign minister Mevlut Cavusoglu said the EU had to stop its "threatening" attitude.
"Make a decision, brother!" Mr Cavusoglu said. "If you want the negotiations to stop, then stop them. If you want them to continue we are ready. But you have to treat us as equal partners. We cannot advance as long as you see us as second-rate country."
In March, Turkey and the EU reached an agreement in which Turkey would stem the flow of migrants to Greece in return for incentives including fast-tracked membership talks, billions of euros in aid for Syrian refugees in Turkey and visa-free travel for Turkish citizens.
The deal has hit a hurdle over Turkey's reluctance to change its anti-terrorism laws - one of the conditions for the lifting of visa restrictions on Turkish citizens travelling to Europe.
On Tuesday, Jean-Claude Juncker, the president of the European Commission, warned Turkey that its crackdown on political opponents and the media goes against EU values.
He too called on Mr Erdogan to immediately say "whether Turkey really wants to be - yes or no - a member of the European Union".
He added that the Turkish leader would only have himself to blame if the EU does not grant visa-free travel in Europe to Turkish citizens soon.
Turkey has been in talks to join the European Union since October 2005, but progress has been held up, often by political opposition and particularly due to resistance from Cyprus, an EU member. The Mediterranean island has been divided since 1974, when Turkish troops occupied its northern third following a coup by supporters of a union with Greece.