istanbul turkey european union affairs minister omer celik say monday talk end country negotiations eu accession amount attack europe found principles comment come day german chancellor angela merkel say clear turkey join eu would talk eu leaders end stall accession process merkel main challenger germany sept. 24 national election martin schulz also promise push end turkey eu negotiations elect chancellor build berlin wall bricks populism celik tweet turkey keep go head hold high european country european democracy say turkey say talk end eu accession undermine europe