German Chancellor Angela Merkel is visiting Ankara to discuss measures to stem the flow of refugees bound for Europe, as tens of thousands of Syrians remained stranded at the border with Turkey after fleeing a Russia-backed government offensive in Aleppo.

"We should be clear that no country is being threatened with suspension from Schengen," European Commissioner for Migration, Home Affairs and Citizenship Dimitris Avramopoulos on Friday said in an interview with EurActiv.

Prime Minister Alexis Tsipras received on Friday visiting French Interior Minister Bernard Cazeneuve and German Interior Minister Thomas De Maiziere at the Maximos mansion.