Leaders from the European Union and Turkey will gather in Brussels on Sunday for a summit on the migration crisis.

Tens of thousands of refugees and migrants have travelled through Turkey to Europe in 2015 so the EU will ask Turkey to better patrol its borders to stem the flow of migration.

In return, Ankara wants €3bn (£2.11bn; $3.17bn) and concessions including allowing Turkish people to travel to Europe without visas.

The BBC's Istanbul correspondent Mark Lowen reports.