A European Union official urged Turkey on Thursday to amend its tough anti-terrorism laws so the EU can lift its visa restrictions — a key incentive in a deal to stop migrants crossing the Aegean Sea.

EU Migration Commissioner Dimitris Avramopoulos held talks with Turkish officials after they warned they would suspend a March migrant deal if the visa restrictions weren't lifted for Turkish nationals. The deal has drastically reduced the number of migrants and refugees from crossing to Greece and onward to wealthier EU countries, such as Germany, France and Sweden.

"Since March, Turkey has made considerable progress," Avramopoulos said. "But there are still outstanding benchmarks to be met. And the European Union is fully committed to help Turkey achieve those."

Plans to loosen visa restrictions have run into trouble over Turkey's refusal to amend its anti-terror laws at a time when it is fighting heightened threats from Kurdish rebels and the Islamic State group.

Turkey has also launched a crackdown after a failed military coup on July 15, rooting out thousands of alleged supporters of U.S.-based Islamic cleric Fethullah Gulen. The government blames Gulen for the uprising and considers him to be a terrorist. Gulen denies any involvement.

"Let me clear on a very important issue. The European Union remains committed to keep the momentum and dialogue on visa liberalization. A lot has been achieved during the last months, and we want to further build on these achievements," Avramopoulos said.

Turkey's minister for EU affairs, Omer Celik, told a joint media conference that Turkey is committed to the framework of the March 18 agreement.

"What we expect is that our allies and friends do what they promised to do," he said.

EU President Martin Schulz was also in Ankara on Thursday trying to restore dialogue amid the fallout from the failed coup that has fueled diplomatic tensions.

Turkey has complained of a lack of support from the West and denounced the criticism of the scope of its crackdown — with tens of thousands detained or fired from their jobs — following the coup attempt.