The two-day 12th annual summit of 15 regional presidents from Central Europe dedicated to European integrations, began in Zagreb on Friday, DPA reported. Albania, Austria, Bosnia-Herzegovina, Bulgaria, Czech Republic, Italy, Hungary, Macedonia. Moldova, Germany, Poland, Romania, Slovakia, Slovenia, Serbia-Montenegro, Ukraine and the host Croatia are the countries that attend the conference. On Friday morning, some presidents have still not arrived to Zagreb due to the fog at the airport. Issues during the summit will include European integration, cooperation and the integration of non-European Union member states into discussions on the future of Europe, it said. Presidents are also to discuss what kind of economic and social model is suitable for united Europe. Welcoming the participants, the chairman of the summit, Croatian President Stjepan Mesic, said European Union enlargement was the only way Europe should go. "The integration of Europe is a unique, millennium endeavour which has no alternative and which needs to be completed in the interest of European countries as well as the whole world. European integration must neither be brought into question nor stopped," Mesic said. He added the successful continuation of European integration called for an intensive campaign of informing citizens, not only in European Union member states, but also in candidate states and those yet to obtain candidate status, so that the widest European public could become aware of the advantages of integration.