The next transfer of migrants to Turkey from Greece under a controversial deal with the EU has been postponed until later this week at Athens' request, a Turkish official said Tuesday.

"It has been postponed to Friday" from Wednesday after the first transfer of over 200 migrants took place on Monday, the official told AFP. "Greece could not send the people. Everything is ready here but we received a message from the Greek side," added the official, asking not to be named.