EU leaders are holding talks with Turkish Prime Minister Ahmet Davutoglu in Brussels in an attempt to reach a deal over the migrant crisis.
An EU proposal would see Turkey offered financial aid and political concessions in return for taking back all migrants travelling to Greece.
EU leaders have watered down the incentives and correspondents say it is unclear if a deal can be done.
Nevertheless, Mr Davutoglu said he was hopeful of finding "common ground".
But he added that he wanted to keep a "humanitarian perspective" on the crisis.
EU leaders agreed on a joint position to put to Turkey after late-night talks. The plan suggests that for every Syrian refugee sent back, another Syrian would be resettled in the EU directly from refugee camps in Turkey.
Ahead of Friday's talks, German Chancellor Angela Merkel said that Turkey had to meet international standards of protection for all migrants.