The summit is to mark the EU's 60th anniversary and to outline its future after Britain leaves. London is to trigger the procedure on Wednesday next week.
Prime Minister Beata Szydlo insisted today the declaration should secure EU unity, close defense cooperation with NATO, a strengthening of the parliaments of the member states and equal rights on the common market.
"If the declaration does not include points that are of priority to Poland, we will not accept the declaration," Szydlo said on TVN24.