The European Union's ambassador to Turkey, German diplomat Hansjoerg Haber, is resigning early from his post amid tensions between Brussels and Ankara over a joint migration deal and concerns about a clampdown on Turkish media and the opposition.
Turkey has helped the EU stem a migration surge into the bloc that reached more than 1 million people last year, in return for aid and benefits. But the deal has become bogged down in a row over visa-free access to the EU for Turkish citizens.
"I can confirm that Ambassador Haber, head of the EU delegation in Ankara, resigned and will be leaving his current post as of 1 August 2016," an EU spokeswoman said on Tuesday, without stating any reasons for the move.
"All the necessary steps are being taken to swiftly appoint a new ambassador," she added.
Haber took up his post in Turkey in September. Last month, the Turkish Foreign Ministry summoned Haber to discuss remarks critical of the EU-Turkey migration deal that was struck in March.
Maja Kocijancic, a spokeswoman for EU foreign policy chief Federica Mogherini, insisted Tuesday that relations with Ankara remain strong.
"Turkey is a key partner, it's a [EU membership] candidate country," she said. "Contacts are ongoing at all levels and work continues."
Since the migration deal was struck, the flow of people from Turkey to EU member Greece has reduced to a trickle. Ankara agreed to take back those who undertake the crossing, in return for aid and benefits such as the prospect of visa-free EU access.
But implementation has become bogged down by Turkey's refusal to meet one of the EU's visa liberalization benchmarks, requiring a narrower definition of terrorism. There are concerns that Ankara has used an anti-terrorism law to crack down on the media and government opposition.
Turkey, meanwhile, insists that visa liberalization is a key condition for its cooperation over the migration issue.
Ankara will "never" change its anti-terrorism law, Turkish Prime Minister Binali Yildirim said during a parliamentary group meeting on Tuesday, adding that the country would rather forgo visa-free EU access.
EU officials have also voiced concern over a Turkish decision last month to lift the immunity of 138 parliamentarians, including nearly all pro-Kurdish lawmakers.
Meanwhile, Turkish President Recep Tayyip Erdogan called late Monday for progress in his country's EU membership negotiations. "Nobody should put our patience to the test," he told the state-run Anadolou news agency.
British Prime Minister David Cameron said last month that, at the current rate, it would take Turkey until the year 3,000 to join the EU.