[German Chancellor Angela Merkel, left,speaks with French President Francois Hollande, center, and Greek Prime Minister Alexis Tsipras, right, during a round table meeting at an EU summit in Brussels on Thursday, Feb. 18, 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/Geert Vanden Wijngaert)]BERLIN (AP) — Austria raised the prospect of even tighter limits on the number of asylum seekers entering the country Friday while Hungary said it is shutting three railway border crossings with Croatia, highlighting the disarray within the European Union over migrants.