The EU must accept Turkey's internal security and terrorism concerns, an EU commissioner said Saturday.

"Turkey and Europe need each other," said Dimitris Avramopoulos, EU commissioner for migration, home affairs and citizenship said at the Delphi Economic Forum IV, held in Athens between Feb. 28 and March 3. Referring to the Turkey-EU deal to tackle the migrant crisis, Avramopoulos said Ankara has fulfilled many criteria for visa liberalization under the agreement and added that the EU needs to show understanding to Turkey in the issue of domestic security and terrorism.

Turkey and the EU signed a refugee deal in March 2016, to discourage irregular migration across the Aegean Sea by taking stricter measures against human traffickers and improving the conditions of the nearly 4 million refugees in Turkey. The March 2016 deal employs a one-for-one formula under which failed asylum seekers in Europe are returned to Turkey, while Syrian refugees are resettled in EU states in a quota system. As another part of the deal, the EU said it would open two chapters in Ankara's EU accession negotiations, provide funding for refugees and grant visa-free travel to Turkish citizens to the Schengen zone. Ankara has criticized the EU for not holding to its promises and for not granting visa-free travel within the Schengen zone. Stressing that the doors for Turkey's membership to the EU were not closed, Avramopoulos said that Turkey joining the bloc would benefit both sides.

Turkey's journey of more than five decades en route to becoming a member of the EU has seen numerous ups and downs. Despite efforts of reforms and modernization in policies at home, Turkey has been waiting for membership as the EU keeps dragging its feet on the process, which began in 1963.

The objections revolving around why Turkey couldn't become a member have also dramatically changed. Instead of a lack of sufficient alignments in Turkish laws, many European leaders rejected the prospect of Turkey's EU membership from an identity-centered perspective and for political reasons.

Recalling that Russian President Vladimir Putin was the first to reach out to Turkey after the July 15, 2016, coup attempt, Avramopoulos noted that President Recep Tayyip Erdoğan "didn't move away from EU." The Gülenist Terror Group (FETÖ) and its U.S.-based leader Fetullah Gülen orchestrated the defeated coup of July 15 which killed 251 people and injured nearly 2,200.