German Interior Minister Thomas de Maiziere arrives for an statement in Wittenberg, Germany, October 31, 2017. German police arrested a 19-year-old Syrian suspected of planning an Islamist-motivated bomb attack in Schwerin in Germany. REUTERS/Hannibal Hanschke 

German Interior Minister Thomas de Maiziere and his wife Martina attend the 500th anniversary of the Reformation at the Castle Church in Wittenberg, Germany, October 31, 2017. REUTERS/Hannibal Hanschke 

German Interior Minister Thomas de Maiziere arrives for the exploratory talks about forming a new coalition government held by CDU/CSU in Berlin, Germany, October 30, 2017. REUTERS/Axel Schmidt 

Minister of the Interior Thomas de Maiziere, Minister for Economics and Interior Brigitte Zypries, Minister for Foreign Affairs Sigmar Gabriel and Chancellor Angel Merkel attend the ceremony to receive dismissal certificate from German President Frank-Walter Steinmeier at Bellvue Palace in Berlin, Germany, October 24, 2017. REUTERS/Fabrizio Bensch 

German Finance Minister Wolfgang Schaeuble and German Interior Minister Thomas de Maiziere arrive for the weekly cabinet meeting at the Chancellery in Berlin, Germany, October 18, 2017. REUTERS/Hannibal Hanschke 

German Interior Minister Thomas de Maiziere arrives for the weekly cabinet meeting at the Chancellery in Berlin, Germany, September 20, 2017. REUTERS/Hannibal Hanschke 

German Interior Minister Thomas de Maiziere and Wilfried Karl president of ZITiS, give a statement to the media during a visit of the new Centre for Information Technology of Security Authorities (ZITiS) in Munich, Germany September 14, 2017. REUTERS/Michaela Rehle 

Wilfried Karl, president of ZITiS welcomes German Interior Minister Thomas de Maiziere as he visits the new Centre for Information Technology of Security Authorities (ZITiS) in Munich, Germany September 14, 2017. REUTERS/Michaela Rehle 

Head of German federal police Dieter Romann (R) talks to German Interior Minister Thomas de Maiziere during a reception of Germany's safety authority in Berlin, Germany September 4, 2017. REUTERS/Fabrizio Bensch 

(L-R) German Interior Minister Thomas de Maiziere, Head of German federal police Dieter Romann, Chief Commissioner of Germany's Bundeskriminalamt (BKA) Federal Crime Office Holger Muench, head of the German Federal Office for the Protection of the Constitution (Bundesamt fuer Verfassungsschutz) Hans-Georg Maassen and President of the German Federal Intelligence Agency (BND) Bruno Kahl attend a reception of Germany's safety authority in Berlin, Germany September 4, 2017. REUTERS/Fabrizio Bensch 

(L-R) Head of German federal police Dieter Romann, Chief Commissioner of Germany's Bundeskriminalamt (BKA) Federal Crime Office Holger Muench, German Interior Minister Thomas de Maiziere, head of the German Federal Office for the Protection of the Constitution (Bundesamt fuer Verfassungsschutz) Hans-Georg Maassen and President of the German Federal Intelligence Agency (BND) Bruno Kahl attend a reception of Germany's safety authority in Berlin, Germany September 4, 2017. REUTERS/Fabrizio Bensch 

German Interior Minister Thomas de Maiziere is briefed on the facial recognition technology project at the Suedkreuz trainstation in Berlin, Germany, August 24, 2017. REUTERS/Wolfgang Kumm/POOL 

German Interior Minister Thomas de Maiziere is briefed on the facial recognition technology project at the Suedkreuz trainstation in Berlin, Germany, August 24, 2017. REUTERS/Wolfgang Kumm/POOL 

German Interior Minister Thomas de Maiziere is briefed on the facial recognition technology project at the Suedkreuz trainstation in Berlin, Germany, August 24, 2017. REUTERS/Wolfgang Kumm/POOL 

German Interior Minister Thomas de Maiziere is briefed on the facial recognition technology project at the Suedkreuz trainstation in Berlin, Germany, August 24, 2017. REUTERS/Wolfgang Kumm/POOL 

German Interior Minister Thomas de Maiziere is briefed on the facial recognition technology project at the Suedkreuz trainstation in Berlin, Germany, August 24, 2017. REUTERS/Wolfgang Kumm/POOL 

German Interior Minister Thomas de Maiziere (L) talks to Health Minister Hermann Groehe at the weekly cabinet meeting at the Chancellery in Berlin, Germany, August 23, 2017. REUTERS/Fabrizio Bensch 

German Interior Minister Thomas de Maiziere attends the weekly cabinet meeting at the Chancellery in Berlin, Germany, August 23, 2017. REUTERS/Fabrizio Bensch 

German Interior Minister Thomas de Maiziere attends the weekly cabinet meeting at the Chancellery in Berlin, Germany, August 16, 2017. REUTERS/Axel Schmidt 

German Interior Minister Thomas de Maiziere attends the weekly cabinet meeting at the Chancellery in Berlin, Germany, August 16, 2017. REUTERS/Axel Schmidt 

German Interior Minister Thomas de Maiziere speaks with members of the GSG 9 unit of Bundespolizei, Germany's federal police, during the opening of a new headquarters for special forces and anti-terror units in Berlin, Germany August 8, 2017. REUTERS/Hannibal Hanschke 

German Interior Minister Thomas de Maiziere speaks with members of the GSG 9 unit of Bundespolizei, Germany's federal police, during the opening of a new headquarters for special forces and anti-terror units in Berlin, Germany August 8, 2017. REUTERS/Hannibal Hanschke 

French President Emmanuel Macron (C Right, Rear) and German Chancellor Angela Merkel (C Left, Rear), stand as from L-R, German Interior Minister Thomas de Maiziere, French Minister of Europe and Foreign Affairs Jean-Yves Le Drian, European Commission Vice-President and EU Commissioner for Foreign Affairs and Security Policy Federica Mogherini, and German Minister of State for Europe at the Federal Foreign Office Michael Roth pose after they signed documents during the launch of the “Alliance for Sahel” at the Elysee Palace in Paris, France, July 13, 2017. REUTERS/Patrick Kovarik/Pool 

French President Emmanuel Macron (R Rear) and German Chancellor Angela Merkel (L Rear), stand as from L-R, German Interior Minister Thomas de Maiziere, French Minister of Europe and Foreign Affairs Jean-Yves Le Drian, European Commission Vice-President and EU Commissioner for Foreign Affairs and Security Policy Federica Mogherini, and German Minister of State for Europe at the Federal Foreign Office Michael Roth sign documents during the launch of the “Alliance for Sahel” at the Elysee Palace in Paris, France, July 13, 2017. REUTERS/Patrick Kovarik/Pool 

German Interior Minister Thomas de Maiziere attends the weekly cabinet meeting at the Chancellery in Berlin, Germany, July 12, 2017. REUTERS/Fabrizio Bensch 

German Interior Minister Thomas de Maiziere attends the weekly cabinet meeting at the Chancellery in Berlin, Germany, July 5, 2017. REUTERS/Axel Schmidt 

Juergen Christian Mertens, Steffen Russ, Thomas Przybylla, Andy Grote, Hartmut Dudde and Dierk Hansen and German Interior Minister Thomas de Maiziere pose with special police ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere during a statement at the Messe ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere and Hamburg Interior Minister Andy Grote arrive for a statement at the Messe ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere and Hamburg Interior Minister Andy Grote talk to journalists at the Messe ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere and Hamburg Interior Minister Andy Grote talk to journalists at the Messe ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere, Hamburg Interior Minister Andy Grote talk to special police ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere, Hamburg Interior Minister Andy Grote talk to special police ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere, Hamburg Interior Minister Andy Grote talk to special police ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere, Hamburg Interior Minister Andy Grote talk to special police ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere, Hamburg Interior Minister Andy Grote talk to special police ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere, Hamburg Interior Minister Andy Grote (L) and chief of protocol from the German Foreign Ministry Juergen Christian Mertens pose at the Messe ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere, Hamburg Interior Minister Andy Grote (L) and chief of protocol from the German Foreign Ministry Juergen Christian Mertens pose at the Messe ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere, Hamburg Interior Minister Andy Grote (L) and chief of protocol from the German Foreign Ministry Juergen Christian Mertens pose at the Messe ahead the G20 summit in Hamburg, Germany, July 4, 2017. REUTERS/Christian Charisius/POOL 

German Interior Minister Thomas de Maiziere and Hans-Georg Maassen, head of the German Federal Office for the Protection of the Constitution (Bundesamt fuer Verfassungsschutz) addresses a news conference to introduce the agency's 2016 report on militant threats to the constitution in Berlin, Germany, July 4, 2017. REUTERS/Axel Schmidt 

German Interior Minister Thomas de Maiziere and Hans-Georg Maassen, head of the German Federal Office for the Protection of the Constitution (Bundesamt fuer Verfassungsschutz) addresses a news conference to introduce the agency's 2016 report on militant threats to the constitution in Berlin, Germany, July 4, 2017. REUTERS/Axel Schmidt 

German Interior Minister Thomas de Maiziere and Foreign Minister Sigmar Gabriel attend a pontifical requiem mass for late former German Chancellor Helmut Kohl in the cathedral in Speyer, Germany, July 1, 2017. REUTERS/Arne Dedert/Pool 

German Interior Minister Thomas de Maiziere and Foreign Minister Sigmar Gabriel attend a pontifical requiem mass for late former German Chancellor Helmut Kohl in the cathedral in Speyer, Germany, July 1, 2017. REUTERS/Marijan Murat/Pool 

German Interior Minister Thomas de Maiziere and Foreign Minister Sigmar Gabriel attend a pontifical requiem mass for late former German Chancellor Helmut Kohl in the cathedral in Speyer, Germany, July 1, 2017. REUTERS/Arne Dedert/Pool 

German interior Minister Thomas de Maiziere and former Hesse State Prime Minister Roland Koch attend a pontifical requiem mass for late former German Chancellor Helmut Kohl in the cathedral in Speyer, Germany, July 1, 2017. REUTERS/Marijan Murat/Pool 

German Interior Minister Thomas de Maiziere poses for press with drones during a drone workshop in Berlin, Germany June 27, 2017. REUTERS/Hannibal Hanschke 

German Interior Minister Thomas de Maiziere poses for press with drones during a drone workshop in Berlin, Germany June 27, 2017. REUTERS/Hannibal Hanschke 

German Health Minister Hermann Groehe, German Agriculture Minister Christian Schmidt, German Defence Minister Ursula von der Leyen, German Interior Minister Thomas de Maiziere, German Education and Research Minister Johanna Wanka and German Finance Minister Wolfgang Schaeuble attend a memorial service for late former chancellor Helmut Kohl at the Hedwig Cathedral in Berlin, Germany, June 27, 2017. REUTERS/John MacDougall/POOL 

German Chancellor Angela Merkel and German Interior Minister Thomas de Maiziere arrive for a memorial service for the former Chancellor Helmut Kohl in Berlin, Germany June 27, 2017. REUTERS/Hannibal Hanschke 

German Chancellor Angela Merkel and German Interior Minister Thomas de Maiziere arrive for a memorial service for the former Chancellor Helmut Kohl in Berlin, Germany June 27, 2017. REUTERS/Hannibal Hanschke 

German Interior Minister Thomas de Maiziere writes a message in a book of condolence for former chancellor Helmut Kohl at the Chancellery in Berlin, Germany June 21, 2017. REUTERS/Stefanie Loos 

German Interior Minister Thomas de Maiziere attends the weekly cabinet meeting at the Chancellery in Berlin, Germany, May 31, 2017. REUTERS/Hannibal Hanschke 

German Interior Minister Thomas de Maiziere (2-L), his wife Martina (L), President Frank-Walter Steinmeier (R) and his wife Elke Buedenbender attend the closing service of the German Protestant Church Congress Kirchentag in Wittenberg, Germany May 28, 2017. REUTERS/Fabrizio Bensch 

German interior minister Thomas de Maiziere attends the opening service of the German protestant church congress Kirchentag in Berlin, Germany, May 24, 2017. REUTERS/Fabrizio Bensch 

German Interior Minister Thomas de Maiziere uses his mobile phone as he attends a cabinet meeting in Berlin, Germany, May 24, 2017. REUTERS/Fabrizio Bensch 

German Interior Minister Thomas de Maiziere (L) and Justice Minister Heiko Maas attend a cabinet meeting in Berlin, Germany, May 24, 2017. REUTERS/Fabrizio Bensch 

German Interior Minister Thomas de Maiziere attends the weekly cabinet meeting at the Chancellery in Berlin, Germany, May 10, 2017. REUTERS/Fabrizio Bensch 

German Interior Minister Thomas de Maiziere attends the weekly cabinet meeting at the Chancellery in Berlin, Germany, May 10, 2017. REUTERS/Fabrizio Bensch 

German Chancellor Angela Merkel, Foreign Minister Sigmar Gabriel and Interior Minister Thomas de Maiziere before a lower house of parliament Bundestag session in Berlin, Germany, April 27, 2017. REUTERS/Hannibal Hanschke 

German Foreign Minister Sigmar Gabriel and Interior Minister Thomas de Maiziere before a lower house of parliament Bundestag session in Berlin, Germany, April 27, 2017. REUTERS/Hannibal Hanschke