EU leaders have approved an action plan with Turkey to help stem the flood of migrants in return for concessions from Brussels, including easier visa access.
"Our intensified meetings with Turkish leaders ... were devoted to one goal: stemming the migratory flows that go via Turkey to the EU. The action plan is a major step in this direction," European Council President Donald Tusk said after a summit of all 28 EU leaders in Brussels.
Tusk said Turkey would have to meet its commitments to help control the flow of migrants, mostly fleeing the war in Syria, and ensure that their asylum requests were properly dealt with.
"We need a response and an adequate response from the Turkish side; they are our partners in the crisis and the 'more for more' principle applies," he told reporters.
European Commission head Jean-Claude Juncker said the European Union had agreed to speed up work on easing visa access for Turkey, a candidate for EU membership, but he stressed Ankara would not get a free ride.
"We have agreed with our Turkish partners that the visa liberalisation process will be accelerated but this does not mean that we will step away from the basic criteria."
Juncker said there would be a clear link between granting Turkey easier visa access, as would be expected for a country seeking EU membership, and its commitment to helping manage the migrant crisis.
Turkey is home to some 2.2 million Syrian refugees and the action plan provides for increased EU financial and technical aid to help Ankara cope with them.
Turkey's EU accession talks have been stalled amid concerns over its human rights record and suspicions it has its own agenda in Syria.