The presidents of ten EU countries will attend the meeting to discuss various issues including increasing trust in the European Union and the transformation of the Balkan region.
This year's meeting will be hosted by Bulgarian President Rosen Plevneliev.
Other participants include Joachim Gauck, Federal President of Germany; Sergio Mattarella, President of the Italian Republic; and Andrzej Duda, President of the Republic of Poland.
The Arraiolos Group has convened every year since 2003, for informal discussions at presiden-tial level.
