The European Union's efforts to hamper terms for Turkey's visa free travel to Europe are totally unacceptable, Selim Yenel, Turkey's ambassador to the EU told the Financial Times.

Under a deal with the EU late last year, Turkey agreed to take back refugees from Greece while Turkish nationals were promised a relaxation of the visa regime in Europe.

"If it is not carried out, no-one would expect Turkey to adhere its commitments," Prime Minister Ahmet Davutoğlu said in a press conference in Ankara on Monday.

According to several European diplomats, EU's visa free travel promise might include an emergency brake that allows for limitations under certain circumstances and might only cover businessmen and students.

"They are probably getting cold feet since we are fulfilling the benchmarks," Selim Yenel told the FT and added that Turkey expects the EU to keep its word to continue to trust the EU.

The visa free travel for Turkish citizens is expected to be introduced by June.