[European Council President Donald Tusk speaks during a media conference at an EU summit in Brussels on Friday, Feb. 19, 2016. European Union leaders are holding a summit in Brussels on Thursday and Friday to hammer out a deal designed to keep Britain in the 28-nation bloc. (AP Photo/Virginia Mayo)]BRUSSELS (AP) — The European Union has called an extraordinary summit with Turkey for early March to coordinate efforts to stem the flow of migrants across the Aegean into Greece.