COLOGNE, GERMANY - SEPTEMBER 29: Turkish President Recep Tayyip Erdogan speaks during the opening ceremony of new Cologne Central Mosque in Cologne, Germany on September 29, 2018. ( Abdülhamid Hoşbaş - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: Turkish President Recep Tayyip Erdogan (R) stands next to the President of Religious Affairs of Turkey Ali Erbas (L) as he leads a pray during the opening ceremony of new Cologne Central Mosque in Cologne, Germany on September 29, 2018. ( Kayhan Özer - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: Turkish President Recep Tayyip Erdogan attends the opening ceremony of new Cologne Central Mosque in Cologne, Germany on September 29, 2018. ( Abdülhamid Hoşbaş - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: Turkish President Recep Tayyip Erdogan (R) and President of Religious Affairs of Turkey Ali Erbas (C) pray during the opening ceremony of new Cologne Central Mosque in Cologne, Germany on September 29, 2018. ( Abdülhamid Hoşbaş - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: Turkish President Recep Tayyip Erdogan speaks during the opening ceremony of new Cologne Central Mosque in Cologne, Germany on September 29, 2018. ( Abdülhamid Hoşbaş - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: Turkish President Recep Tayyip Erdogan greets the crowd during the opening ceremony of new Cologne Central Mosque in Cologne, Germany on September 29, 2018. ( Cem Öksüz - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: Turkish President Recep Tayyip Erdogan greets the crowd during the opening ceremony of new Cologne Central Mosque in Cologne, Germany on September 29, 2018. ( Kayhan Özer - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: Turkish President Recep Tayyip Erdogan delivers a speech during the opening ceremony of new Cologne Central Mosque in Cologne, Germany on September 29, 2018. ( Kayhan Özer - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: Turkish President Recep Tayyip Erdogan (right 2), his wife Emine Erdogan (R) and President of Religious Affairs of Turkey Ali Erbas (left 3) attend the opening ceremony of new Cologne Central Mosque in Cologne, Germany on September 29, 2018. ( Kayhan Özer - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: Turkish President Recep Tayyip Erdogan (R), his wife Emine Erdogan (right 2) and President of Religious Affairs of Turkey Ali Erbas (L) chat with kids during the opening ceremony of new Cologne Central Mosque in Cologne, Germany on September 29, 2018. ( Kayhan Özer - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: Turkish President Recep Tayyip Erdogan (left 2 ) and his wife Emine Erdogan (L) attend the opening ceremony of new Cologne Central Mosque in Cologne, Germany on September 29, 2018. ( Kayhan Özer - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: Children wearing Turkish Flag t-shirts are seen as people are gathering around the new Cologne Central Mosque which will be opened by Turkish President Recep Tayyip Erdogan in Cologne, Germany on September 29, 2018. ( Abdülhamid Hoşbaş - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: German police take security measures as people are gathering around the new Cologne Central Mosque which will be opened by Turkish President Recep Tayyip Erdogan in Cologne, Germany on September 29, 2018. ( Abdülhamid Hoşbaş - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: People gathering around the new Cologne Central Mosque which will be opened by Turkish President Recep Tayyip Erdogan in Cologne, Germany on September 29, 2018. ( Abdülhamid Hoşbaş - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: People gathering around the new Cologne Central Mosque which will be opened by Turkish President Recep Tayyip Erdogan in Cologne, Germany on September 29, 2018. ( Abdülhamid Hoşbaş - Anadolu Agency )

COLOGNE, GERMANY - SEPTEMBER 29: People gathering around the new Cologne Central Mosque which will be opened by Turkish President Recep Tayyip Erdogan in Cologne, Germany on September 29, 2018. ( Abdülhamid Hoşbaş - Anadolu Agency )