Turkish and EU leaders have gathered in Brussels for an emergency summit on tackling Europe’s worst refugee crisis since World War Two.
The EU aims to stem the flow of migrants and plans to declare the route north through the Balkans closed.
It will press Turkey to take back economic migrants and has pledged to give Ankara €3bn (£2.3bn; $3.3bn).
Last year, more than a million people entered the EU illegally by boat, mainly going from Turkey to Greece.
Many migrants leave Greece in a bid to reach northern Europe, but eight countries have introduced temporary border controls.
Some 13,000 migrants are currently stranded in northern Greece, after Macedonia, backed by Croatia, Hungary and Slovenia, closed its border to all but a trickle of migrants.
The summit will be in two parts – the first session from 11:30 GMT will involve Turkey, while in the afternoon UK Prime Minister David Cameron will join other EU leaders in seeking to reach a common approach to the crisis.
The EU is expected to ask Turkey to take back thousands of migrants who do not qualify for asylum. In return the EU will discuss plans to resettle in Europe some refugees already in Turkey.