The resumption of the dialogue, after four years of interruption, was made at a meeting of the EU-Turkey Association Council in Brussels.
Ankara was represented by Turkish Foreign Minister Mevlut Cavusoglu, and the European institutions by Federica Mogherini, the head of European diplomacy, and Johannes Hahn, European Commissioner for Enlargement.
On the agenda: Turkey's accession negotiations with the European Union, stalled for many years.
Federica Mogherini expressed her "deep concern" for the rule of law in Turkey.
"Systematic delays, detentions, insufficient evidence, criminal prosecution of persons who exercise their fundamental rights, such as freedom of expression or freedom of assembly." All this casts doubt on the respect of the principle of the presumption of innocence and the right to a fair trial in Turkey, "she said.
Relations between Brussels and Ankara have become very tense since the failed coup attempt of July 2016 and the crackdown on opponents and journalists that followed.
But Turkey wants to continue the accession negotiations, as recalled by the Turkish Foreign Minister. Ankara hopes to obtain visa liberalisation for its citizens and calls on member states to remove obstacles to the extension of the Customs Union.