Germany's Chancellor Angela Merkel (R) speaks with European Council President Donald Tusk during an European leaders summit in Brussels on October 20, 2017. EU leaders agreed to start preparatory talks on the bloc's relationship with Britain after Brexit, giving some progress for embattled Prime Minister Theresa May to take back home. / AFP PHOTO / EMMANUEL DUNAND

Germany's Chancellor Angela Merkel (R) speaks with European Council President Donald Tusk during an European leaders summit in Brussels on October 20, 2017. EU leaders agreed to start preparatory talks on the bloc's relationship with Britain after Brexit, giving some progress for embattled Prime Minister Theresa May to take back home. / AFP PHOTO / EMMANUEL DUNAND

EU-Gipfel in Brussel (171020) -- BRUSSELS, Oct. 20, 2017 -- German Chancellor Angela Merkel (R) talks with European Council President Donald Tusk prior to the second day of two-day EU Summit in Brussels, Belgium, early on Oct. 20, 2017. ) (zw) BELGIUM-BRUSSELS-EU-SUMMIT-SECOND DAY YexPingfan PUBLICATIONxNOTxINxCHN

EU-Gipfel in Brussel (171020) -- BRUSSELS, Oct. 20, 2017 -- German Chancellor Angela Merkel (R) talks with European Council President Donald Tusk prior to the second day of two-day EU Summit in Brussels, Belgium, early on Oct. 20, 2017. ) (zw) BELGIUM-BRUSSELS-EU-SUMMIT-SECOND DAY YexPingfan PUBLICATIONxNOTxINxCHN

European Council President Donald Tusk attends an European leaders summit in Brussels on October 20, 2017. EU leaders agreed to start preparatory talks on the bloc's relationship with Britain after Brexit, giving some progress for embattled Prime Minister Theresa May to take back home. / AFP PHOTO / EMMANUEL DUNAND

EU-Gipfel in Brussel (171020) -- BRUSSELS, Oct. 20, 2017 -- German Chancellor Angela Merkel (R) talks with European Council President Donald Tusk prior to the second day of two-day EU Summit in Brussels, Belgium, on Oct. 20, 2017. ) (zw) BELGIUM-BRUSSELS-EU-SUMMIT-SECOND DAY YexPingfan PUBLICATIONxNOTxINxCHN

EU-Gipfel in Brussel (171020) -- BRUSSELS, Oct. 20, 2017 -- German Chancellor Angela Merkel (R) talks with European Council President Donald Tusk prior to the second day of two-day EU Summit in Brussels, Belgium, early on Oct. 20, 2017. ) (zw) BELGIUM-BRUSSELS-EU-SUMMIT-SECOND DAY YexPingfan PUBLICATIONxNOTxINxCHN

EU-Gipfel in Brussel (171020) -- BRUSSELS, Oct. 20, 2017 -- German Chancellor Angela Merkel (R) talks with European Council President Donald Tusk prior to the second day of two-day EU Summit in Brussels, Belgium, early on Oct. 20, 2017. ) (zw) BELGIUM-BRUSSELS-EU-SUMMIT-SECOND DAY YexPingfan PUBLICATIONxNOTxINxCHN

Brussels , 20/10/2017 European Council ( Art. 50 - Brexit ) at the Justus Lipsius building . Pix : Donald Tusk Credit : Thierry Roge / Pool / Isopix

Brussels , 20/10/2017 European Council ( Art. 50 - Brexit ) at the Justus Lipsius building . Pix : Donald Tusk Credit : Thierry Roge / Pool / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Donald tusk Credit : Pool / Dany Gys / Isopix

Malta's Prime Minister Joseph Muscat, left, speaks with European Council President Donald Tusk during a round table meeting at an EU summit in Brussels on Thursday, Oct. 19, 2017. British Prime Minister Theresa May headed to a European Union summit Thursday with a pledge to treat EU residents well once Britain leaves the bloc. (AP Photo/Geert Vanden Wijngaert)

European Commission President Jean-Claude Juncker, center left, and European Council President Donald Tusk, center right, walk through the atrium during an EU summit in Brussels on Thursday, Oct. 19, 2017. EU leaders told British Prime Minister Theresa May Thursday to match her goodwill pledges to boost Brexit negotiations with concrete proposals if she really wants to start discussing a future trade deal with the EU by December. (AP Photo/Virginia Mayo)

European Commission President Jean-Claude Juncker, left, and European Council President Donald Tusk participate in a media conference at an EU summit in Brussels on Thursday, Oct. 19, 2017. EU leaders told British Prime Minister Theresa May Thursday to match her goodwill pledges to boost Brexit negotiations with concrete proposals if she really wants to start discussing a future trade deal with the EU by December. (AP Photo/Virginia Mayo)

European Commission President Jean-Claude Juncker, left, and European Council President Donald Tusk participate in a media conference at an EU summit in Brussels on Thursday, Oct. 19, 2017. EU leaders told British Prime Minister Theresa May Thursday to match her goodwill pledges to boost Brexit negotiations with concrete proposals if she really wants to start discussing a future trade deal with the EU by December. (AP Photo/Virginia Mayo)

European Commission President Jean-Claude Juncker, left, and European Council President Donald Tusk participate in a media conference at an EU summit in Brussels on Thursday, Oct. 19, 2017. EU leaders told British Prime Minister Theresa May Thursday to match her goodwill pledges to boost Brexit negotiations with concrete proposals if she really wants to start discussing a future trade deal with the EU by December. (AP Photo/Virginia Mayo)

Jean-Claude Juncker, European Commission President, welcomes the Austrian Minister of Foreign Affairs and leader of the Austrian people's Party in Brussels, on October 19, 2017 on the first day of a summit of European Union (EU) leaders, set to rule out moving to full Brexit trade talks after negotiations stalled. / AFP PHOTO / Aurore Belot

Jean-Claude Juncker , the president of the European Commission (L) welcomes Austrian Foreign Minister and the leader of the Austrian Peoples Party (OeVP), Sebastian Kurz as he arrives prior to the meeting at European Commission headquartersin Brussels, Belgium on 19.10.2017 by Wiktor Dabkowski | usage worldwide

Jean-Claude Juncker , the president of the European Commission (L) welcomes Austrian Foreign Minister and the leader of the Austrian Peoples Party (OeVP), Sebastian Kurz as he arrives prior to the meeting at European Commission headquartersin Brussels, Belgium on 19.10.2017 by Wiktor Dabkowski | usage worldwide

Austrian Foreign Minister and the leader of the Austrian Peoples Party (OeVP), Sebastian Kurz arrives prior to the meeting at European Commission headquartersin Brussels, Belgium on 19.10.2017 by Wiktor Dabkowski | usage worldwide

Jean-Claude Juncker , the president of the European Commission (R) welcomes Austrian Foreign Minister and the leader of the Austrian Peoples Party (OeVP), Sebastian Kurz as he arrives prior to the meeting at European Commission headquartersin Brussels, Belgium on 19.10.2017 by Wiktor Dabkowski | usage worldwide

Jean-Claude Juncker , the president of the European Commission (R) welcomes Austrian Foreign Minister and the leader of the Austrian Peoples Party (OeVP), Sebastian Kurz as he arrives prior to the meeting at European Commission headquartersin Brussels, Belgium on 19.10.2017 by Wiktor Dabkowski | usage worldwide

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Federica Mogherini Credit : Melanie Wenger / Isopix

Brussels , 19/10/2017 European Council ( Art. 50 - Brexit ) at the Justus Lipsius building . Pix : Emmanuel Macron , Jean-Claude Juncker . Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Mark Rutte Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Federica Mogherini / Theresa May Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Mark Rutte / Andrej Plenkovic Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Antonio Tajani / Federica Mogherini Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Mark Rutte / Paolo Gentiloni / Theresa May Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Antonio Tajani / Jean Claude Juncker Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Paolo Gentiloni / Xavier Bettel Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Mark Rutte / Andrej Plenkovic Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Angela Merkel / Antonio Costa Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Mark Rutte / Paolo Gentiloni / Theresa May Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Charles Michel Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Xavier Bettel Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Federica Mogherini / Donald Tusk Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Jean Claude Juncker Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Jean Claude Juncker Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Angela Merkel Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Angela Merkel / Antonio Costa Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Charles Michel Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Round Table Pix : Charles Michel Credit : Pool / Dany Gys / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Juha Sipila Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Juha Sipila Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Beata Szydlo Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Charles Michel Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Alexis Tsipras Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Dalia Grybauskaite Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Klaus Werner Iohannis Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Klaus Werner Iohannis Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Viktor Orban Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Mariano Rajoy Brey Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Andrej Plenkovic Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Antonio Costa Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Antonio Costa Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Bohuslav Sobotka Credit : Frederic Sierakowski / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Theresa May Credit : Melanie Wenger / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Theresa May Credit : Melanie Wenger / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Federica Mogherini Credit : Melanie Wenger / Isopix

Brussels , 19/10/2017 European Council (Art. 50) at the Justus Lipsius building . Pix : Theresa May Credit : Melanie Wenger / Isopix

BRUSSELS, BELGIUM - OCTOBER 19 : High Representative of the European Union for Foreign Affairs and Security Policy, Federica Mogherini (R) and Greek Cypriot leader Nikos Anastasiadis (L) attend the European Council Meeting at the Council of the European Union building on October 19, 2017 in Brussels, Belgium. Leaders attended the meeting to discuss the Iran Nuclear Deal, international relations, refugees, security, defense, digitalization and collaboration. Dursun Aydemir / Anadolu Agency

October 19, 2017 - Brussels, Belgium: Portugese Prime Minister Antonio Costa (L) is talking with the German Chancellor Angela Merkel (R) prior the start of an EU heads of state or government meeting in the EU Council headquarter. EU leaders gathers for a 2 days EU Summit. - NO WIRE SERVICE - Photo: Thierry Monasse/dpa Photo: Thierry Monasse/dpa

October 19, 2017 - Brussels, Belgium: German Chancellor Angela Merkel (L) is talking with the Prime Minister of the United Kingdom Theresa May (C) and the French President Emmanuel Macron (R) prior the start of an EU heads of state or government meeting in the EU Council headquarter. EU leaders gathers for a 2 days EU Summit. - NO WIRE SERVICE - Photo: Thierry Monasse/dpa Photo: Thierry Monasse/dpa

October 19, 2017 - Brussels, Belgium: German Chancellor Angela Merkel (L) is talking with the Prime Minister of the United Kingdom Theresa May (C) and the French President Emmanuel Macron (R) prior the start of an EU heads of state or government meeting in the EU Council headquarter. EU leaders gathers for a 2 days EU Summit. - NO WIRE SERVICE - Photo: Thierry Monasse/dpa Photo: Thierry Monasse/dpa