According to presidential sources who spoke on condition of anonymity due to restrictions on talking to the media, Erdogan and Merkel evaluated the issue during a bilateral talk at the first ever World Humanitarian Summit in Istanbul.

The leaders agreed on a detailed discussion over the demanded amendments in Turkey’s anti-terror laws as part of the deal to lift visa requirements for Turkish citizens.

Europe and Turkey struck a deal in March that stipulated all refugees who reach Europe would be returned to Turkey.

That agreement included EU pledges to donate six billion euros ($6.8 billion) to aid refugees in Turkey, speed up the country’s EU accession and introduce visa-free travel for Turkish nationals.

According to the 28-nation bloc's executive body, Turkey has five remaining benchmarks, out of an initial 72, to fulfill to enable nearly 80 million Turkish citizens to travel freely in the Schengen borderless zone.

The five remaining benchmarks touch on issues including: measures to prevent corruption; data protection in line with EU standards; cooperation with the EU’s law enforcement agency Europol; judicial cooperation on criminal matters with all EU member states and "revising the legislation and practices on terrorism in line with European standards".

However, Erdogan had criticized the terror requirement, saying: "We will go our way; you go yours."

Anadolu Agency