Turkey is to get some EUR 3 B in funding, visa liberalization with the EU, and the prospect of having membership talks renewed, EU and Turkish leaders have decided at a Sunday summit.

In return, Ankara will have to stem the flow of migrants trying to cross from its borders into neighboring Southeastern European countries.

Of the EUR 3 B, some EUR 2.5 B will be a contribution from member states, and the rest will be earmarked from the EU's common budget.

Turkey's PM Ahmet Davutoglu called Sunday's meeting a "historic" event in the EU membership negotiation process.

The visa deal comprises countries from the so-called Schengen borderless area, which excludes Bulgaria and Romania for the moment. Bulgaria's Prime Minister Boyko Borisov earlier suggested his country could only agree on partial liberalization, with Turkish officials possibly being granted a waiver to enter Bulgaria.

Sunday's summit in Brussels is controversially perceived by some of the leaders who believe Europe is turning a blind eye on concerns it previously showed about the political situation and respect for human rights in Turkey for the sake of its own agenda.

The migrant crisis has resurfaced as problem for Europe after the November 13 attacks in Paris, with some of the suspects having arrived via Greece as part of the migrant flow.