European Union governments will consider on Friday whether to provide more money for migrants in Turkey, but will not accept that refugees are used as a bargaining tool, the EU's top diplomat said.

Josep Borrell, the EU’s external policy chief, is chairing a meeting of EU foreign ministers in the Croatian capital Zagreb.

“Turkey has a big burden… and we have to understand that. But at the same time, we cannot accept that migrants are being used as a source of pressure,” he said, referring to Ankara’s decision to open its border with Greece.