Turkish Prime Minister Binali Yildirim condemned on Friday what he said was the lack of a "constructive attitude" on the part of Greek Cypriots, blaming them for the failure of talks to reunify Cyprus.
The UN-backed talks that began in Switzerland on June 28 had been billed as the best chance to end the Mediterranean island's four-decade division but they collapsed early Friday without an agreement.
"The southern Greek Cypriot side unfortunately did not show an expected constructive attitude," Yildirim told reporters in Ankara.
"Turkey will use all of its rights under international law to protect the rights of our brothers and sisters (in northern Cyprus)," he added.
Cyprus has been divided since 1974 when Turkish troops invaded and later occupied its northern third in response to an Athens-inspired coup seeking union with Greece.
It remains one of the world's longest-running political crises despite more than two years of UN-backed efforts to reunite the island.
After a failed referendum on a UN peace blueprint in 2004, the Republic of Cyprus joined the EU as a divided country, while the self-declared Turkish Republic of Northern Cyprus remains recognised only by Ankara.
One of the biggest areas of disagreement was the future of Turkey's troops presence on the island and its security guarantee for Turkish Cypriots.
Turkey maintains more than 35,000 troops in northern Cyprus. Hopes of reunification largely hinge on a drastic reduction of Ankara's military presence.
Turkish Foreign Minister Mevlut Cavusoglu also criticised the Greek side, saying "we did not see positive steps compatible with honesty".
Yildirim and Cavusoglu both emphasised what they said was the Turkish side's constructive role.
The Turks and Turkish Cypriots did "everything in their power" to reach an agreement, Yildirim said.
Cavusoglu said the outcome showed that "within the UN's Good Offices mission's parameters a resolution cannot be found. There is no meaning left in continuing within these parameters".