European leaders have agreed on a deal to curb the flow of migrants into the EU. The plan will be presented to Turkish Prime Minister Ahmet Davutoglu on Friday. Here's what you need to know about the summit so far:

-Earlier Thursday, many EU leaders expressed skepticism about various elements of the deal, including the visa liberalization plans for Turkey, which would allow visa-free travel for Turkey's more than 75 million citizens within the EU

-On the table: Turkey has offered to take back all migrants who have arrived illegally in Greece by crossing the Aegean Sea. In exchange, Turkey has requested a total of 6 billion euros ($6.7 billion) in aid from the EU, on top of rapid visa liberalization and the acceleration of EU accession talks

-Human rights organizations have criticized the deal for undermining the right to asylum, breaching international and EU law

-Speaking to reporters at the airport before leaving for Brussels, Turkish Prime Minister Ahmet Davutoglu said he saw "some difficulties within the EU ... in fulfilling these terms [in Turkey's proposal]." He warned that Turkey would not accept any deal which turned his country into an "open prison" for migrants

-Davutoglu will join EU leaders for breakfast on Friday to continue the talks - and possibly for lunch and dinner as well

Click here to follow our live summit blog.