Turkish President Recep Tayyip Erdogan has suggested he might call a referendum on Turkey's participation in membership talks with the European Union, the state-run Anadolu news agency reports.
He accused the bloc of stalling the process because Turkey is a majority-Muslim country.
Earlier on Wednesday, a senior official in Brussels said the European Union will start negotiations on a new chapter in Turkey's membership bid on June 30, as required in a migration deal struck with Ankara.
Turkey has officially been a candidate for EU membership since 1999, but progress has been slow, hampered by years of opposition from France and Germany, as well as geopolitical tensions over Cyprus.
Erdogan raised the possibility of a referendum on the eve of the vote on Thursday in Britain on remaining in the EU.
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"We could ask, should the talks with the European Union go forward or not," he said.
Disagreements with European governments over this year's migration agreement and visa-free entry for Turks to the EU have exposed the bloc's unreliability, Erdogan said.
"You don't keep your promises," he said. "That's your ugly side. Because Erdogan has unmasked this hateful face, you're cracking up."
Turkey demanded progress on its membership bid in exchange for its help in stemming migrant flows to Europe.
The migration agreement struck by the two sides in March foresees a new negotiating chapter being opened before July.
