EU Council President Tusk said that sending illegal refugees and migrants back from Europe would break the business model of smugglers arranging their sea crossing. Tusk said to migrants not to risk their lives or money to make a perilous trip to Europe "for nothing" but said unilateral actions by European Union states to deal with the crisis must stop.

"We agreed that the refugee flows still remain far too high and that further action is needed. It is for Turkey to decide how best it is to achieve such an action. To many in Europe, the most promising method seems to be a fast and large-scale mechanism to ship back irregular migrants arriving in Greece. It would effectively break the business model of the smugglers," he said.

The ultimate aim was to eliminate the illegal sea transit of migrants from Turkey to Greece, Tusk said after meeting Turkish Prime Minister Ahmet Davutoglu in Ankara and Greek Prime Minister Alexis Tsipras in Athens, although he said no specific numbers had been agreed with the Turks.

"We didn't agree any specific numbers because in fact it is not about numbers, it is about ongoing and permanent process with the final goal which means for me the total reduction and in fact elimination of this sad phenomenon which means illegal migration and this business model of smugglers," he said.

Tusk was on a trip through Balkan states and Turkey to try to drum up support for cohesion on how to deal with hundreds of thousands of migrants – a crisis that threatens to tear the bloc apart – before an EU summit on 7 March. Speaking earlier in Greece, which has been a primary gateway of migrants flooding into Europe for more than a year, Tusk said anyone who was not a refugee should stay away.