Access to the EU's passport-free Schengen area was a key demand by Turkey in an agreement struck in March, while Ahmet Davutoglu was still Prime Minister which somewhat guaranteed the deal’s implementation.
 
But European Union institutions claim Turkey needs to meet certain conditions, including narrowing its definition of terrorism, which has led to the imprisonment of journalists and academics, before visa liberation can be granted.
 
Under the agreement, Turkey has to meet 72 conditions to earn visa-free access to the Schengen area by the end of June. Mr. Erdogan however claims Turkey has done more than enough, while the funds it was promised by the EU, to tackle the refugee flows in return, have not yet been released.
 
German Chancellor Angela Merkel, who met Mr. Erdogan on Monday, said there might not be enough time for the 72 requirements to be met. In which case, Mr. Erdogan threatens to block the EU-Turkey deal on the refugee crisis.
 
Speaking at the close of the World Humanitarian Summit in Istanbul, Mr. Erdogan warned: “If that is not going to happen… no decision and no law in the framework of the readmission agreement [on migrants] will come out of the parliament of the Turkish Republic.”
 
There are fears the whole migrant deal will collapse if the visa dispute is not resolved, as the Turkish president has repeatedly warned.
 
Under the EU-Turkey agreement, migrants who have arrived illegally in Greece since 20 March are to be sent back to Turkey if they do not apply for asylum or if their claim is rejected. For each Syrian migrant returned to Turkey, the EU is to take in another Syrian who has made a legitimate request.
 
Currently 2.75 million Syrian refugees are registered with UN agencies in Turkey, which has a population of 78.7 million people.