Secretary General of the Arab League Ahmed Aboul Gheit (C) speaks with European Union Foreign Policy Chief Federica Mogherini (R) during the 4th EU-League of Arab States Ministerial meeting between Arab and European foreign ministers, to discuss the Syrian and Iraqi crises, at the Arab League Headquarters in Cairo, Egypt December 20, 2016. REUTERS/Amr Abdallah Dalsh 

Spanish Foreign Minister Alfonso Dastis (R) attends before the 4th EU-League of Arab States Ministerial meeting between Arab and European foreign ministers, to discuss the Syrian and Iraqi crises, at the Arab League Headquarters in Cairo, Egypt December 20, 2016. REUTERS/Amr Abdallah Dalsh 

Secretary General of the Arab League Ahmed Aboul Gheit attends during the 4th EU-League of Arab States Ministerial meeting between Arab and European foreign ministers, to discuss the Syrian and Iraqi crises, at the Arab League Headquarters in Cairo, Egypt December 20, 2016. REUTERS/Amr Abdallah Dalsh 

Greek Foreign Minister Nikos Kotzias (R) arrives to attend the 4th EU-League of Arab States Ministerial meeting between Arab and European foreign ministers, to discuss the Syrian and Iraqi crises, at the Arab League Headquarters in Cairo, Egypt December 20, 2016. REUTERS/Amr Abdallah Dalsh 

Spanish Foreign Minister Alfonso Dastis attends before the 4th EU-League of Arab States Ministerial meeting between Arab and European foreign ministers, to discuss the Syrian and Iraqi crises, at the Arab League Headquarters in Cairo, Egypt December 20, 2016. REUTERS/Amr Abdallah Dalsh 

Secretary General of the Arab League Ahmed Aboul Gheit arrives to attend the 4th EU-League of Arab States Ministerial meeting between Arab and European foreign ministers, to discuss the Syrian and Iraqi crises, at the Arab League Headquarters in Cairo, Egypt December 20, 2016. REUTERS/Amr Abdallah Dalsh 

European Union Foreign Policy Chief Federica Mogherini (R) listens to Tunisian Foreign Minister Khemaies Jhinaoui during the speech of Secretary General of the Arab League Ahmed Aboul Gheit at the 4th EU-League of Arab States Ministerial meeting between Arab and European foreign ministers, to discuss the Syrian and Iraqi crises, at the Arab League Headquarters in Cairo, Egypt December 20, 2016. REUTERS/Amr Abdallah Dalsh 

Secretary General of the Arab League Ahmed Aboul Gheit gives his speech during the 4th EU-League of Arab States Ministerial meeting between Arab and European foreign ministers, to discuss the Syrian and Iraqi crises, at the Arab League Headquarters in Cairo, Egypt December 20, 2016. REUTERS/Amr Abdallah Dalsh 

Secretary General of the Arab League Ahmed Aboul Gheit (L) speaks with European Union Foreign Policy Chief Federica Mogherini during the 4th EU-League of Arab States Ministerial meeting between Arab and European foreign ministers, to discuss the Syrian and Iraqi crises, at the Arab League Headquarters in Cairo, Egypt December 20, 2016. REUTERS/Amr Abdallah Dalsh 

European Union Foreign Policy Chief Federica Mogherini gives her speech during the 4th EU-League of Arab States Ministerial meeting between Arab and European foreign ministers, to discuss the Syrian and Iraqi crises, at the Arab League Headquarters in Cairo, Egypt December 20, 2016. REUTERS/Amr Abdallah Dalsh 

A general view shows the 4th EU-League of Arab States Ministerial meeting between Arab and European foreign ministers, to discuss the Syrian and Iraqi crises, at the Arab League Headquarters in Cairo, Egypt December 20, 2016. REUTERS/Amr Abdallah Dalsh 

European Commissioner for Migration and Home Affairs Dimitris Avramopoulos addresses a news conference at the EU Commission headquarters in Brussels, Belgium, December 8, 2016. REUTERS/Francois Lenoir 

European Commissioner for Migration and Home Affairs Dimitris Avramopoulos addresses a news conference at the EU Commission headquarters in Brussels, Belgium, December 8, 2016. REUTERS/Francois Lenoir 

European Commissioner for Migration and Home Affairs Dimitris Avramopoulos addresses a news conference at the EU Commission headquarters in Brussels, Belgium, December 8, 2016. REUTERS/Francois Lenoir 

European Commissioner for Migration and Home Affairs Dimitris Avramopoulos addresses a news conference at the EU Commission headquarters in Brussels, Belgium, December 8, 2016. REUTERS/Francois Lenoir 

European Commissioner for Migration and Home Affairs Dimitris Avramopoulos addresses a news conference at the EU Commission headquarters in Brussels, Belgium, December 8, 2016. REUTERS/Francois Lenoir 

European Commissioner for Migration and Home Affairs Dimitris Avramopoulos addresses a news conference at the EU Commission headquarters in Brussels, Belgium, December 8, 2016. REUTERS/Francois Lenoir 

European Commissioner for Migration and Home Affairs Dimitris Avramopoulos addresses a news conference at the EU Commission headquarters in Brussels, Belgium, December 8, 2016. REUTERS/Francois Lenoir 

People use their mobile phones at the European headquarters of the United Nations in Geneva, Switzerland December 1, 2016. REUTERS/Denis Balibouse 

European Commissioner for Migration and Home Affairs Dimitris Avramopoulos addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir 

European Commissioner for Migration and Home Affairs Dimitris Avramopoulos addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir 

European Commission First Vice-President Frans Timmermans addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir 

European Commission First Vice-President Frans Timmermans addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir 

European Commission Vice-President Valdis Dombrovskis addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir

European Employment, Social Affairs, Skills and Labour Mobility Commissioner Marianne Thyssen addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir

European Economic and Financial Affairs Commissioner Pierre Moscovici addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir

European Employment, Social Affairs, Skills and Labour Mobility Commissioner Marianne Thyssen addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir

European Economic and Financial Affairs Commissioner Pierre Moscovici speaks during a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir

European Economic and Financial Affairs Commissioner Pierre Moscovici speaks at a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir

European Economic and Financial Affairs Commissioner Pierre Moscovici addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir

European Economic and Financial Affairs Commissioner Pierre Moscovici addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir

European Economic and Financial Affairs Commissioner Pierre Moscovici addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir

European Economic and Financial Affairs Commissioner Pierre Moscovici addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir

European Economic and Financial Affairs Commissioner Pierre Moscovici addresses a news conference at the EU Commission headquarters in Brussels, Belgium, November 16, 2016. REUTERS/Francois Lenoir

British Prime Minister Theresa May arrives at the EU Council headquarters for a European Union leaders summit in Brussels, Belgium October 20, 2016. REUTERS/Yves Herman 

British Prime Minister Theresa May arrives at the EU Council headquarters for a European Union leaders summit in Brussels, Belgium October 20, 2016. REUTERS/Yves Herman 

British Prime Minister Theresa May arrives at the EU Council headquarters for a European Union leaders summit in Brussels, Belgium October 20, 2016. REUTERS/Yves Herman 

British Prime Minister Theresa May arrives at the EU Council headquarters for a European Union leaders summit in Brussels, Belgium October 20, 2016. REUTERS/Yves Herman 

A placard reading " STOP TTIP CETA" is seen outside the EU Council headquarters ahead of a European Union leaders summit in Brussels, Belgium October 20, 2016. REUTERS/Yves Herman 

A cyclist rides past a placard reading " STOP TTIP CETA" outside the EU Council headquarters ahead of a European Union leaders summit in Brussels, Belgium October 20, 2016. REUTERS/Yves Herman 

U.N. Secretary-General-designate, Mr. Antonio Guterres of Portugal, addresses the U.N. General Assembly at U.N. headquarters in New York, U.S. October 13, 2016. REUTERS/Lucas Jackson

United Nations Secretary General Ban Ki-moon (L) speaks about Secretary-General-designate, Mr. Antonio Guterres of Portugal (R), at U.N. headquarters in New York, U.S. October 13, 2016. REUTERS/Lucas Jackson

U.N. Secretary-General-designate, Mr. Antonio Guterres of Portugal (C), walks down the center of the aisle at U.N. headquarters in New York, U.S. October 13, 2016. REUTERS/Lucas Jackson

United Nations (U.N.) Secretary General Ban Ki-moon (L) speaks about Secretary-General-designate, Mr. Antonio Guterres of Portugal (R), at U.N. headquarters in New York, U.S. October 13, 2016. REUTERS/Lucas Jackson

Members of the United Nations (U.N.) General Assembly, led by Secretary General Ban Ki-moon, stand for a moment of silence in honor of the passing of Thailand's King Bhumibol Adulyadej at U.N. headquarters in New York, U.S., October 13, 2016. REUTERS/Lucas Jackson TPX IMAGES OF THE DAY

A woman smokes a cigarette outside the European Commission headquarters in Brussels, Belgium, October 13, 2016. REUTERS/Francois Lenoir

A member of his team adjusts the microphone for British Foreign Secretary Boris Johnson as he addresses a meeting of the United Nations Security Council to address the situation in the Middle East during the General Assembly for the 71st session of the U.N. General Assembly at U.N. headquarters in New York, U.S., September 21, 2016. REUTERS/Lucas Jackson

British Foreign Secretary Boris Johnson checks his phone at a meeting of the United Nations Security Council to address the situation in the Middle East during the General Assembly for the 71st session of the U.N. General Assembly at U.N. headquarters in New York, U.S., September 21, 2016. REUTERS/Lucas Jackson

Translators work as U.S. President Barack Obama speaks during a High Level Leaders meeting on Refugees on the sidelines of the United Nations General Assembly at United Nations headquarters in New York City, U.S. September 20, 2016. REUTERS/Brendan McDermid

Philippine President Rodrigo Duterte (L) talks with Chinese Ambassador to the Philippines Zhao Jianhua (R) during the 115th Police Service Anniversary at the Philippine National Police (PNP) headquarters in Quezon city, metro Manila, Philippines August 17, 2016. REUTERS/Noel Celis/Pool 

Spain's acting prime minister and People's Party (PP) leader Mariano Rajoy and party members address supporters at party headquarters after results were announced in Spain's general election in Madrid, Spain, June 27, 2016. REUTERS/Marcelo del Pozo

Spain's acting prime minister and People's Party (PP) leader Mariano Rajoy and party members address supporters at party headquarters after results were announced in Spain's general election in Madrid, Spain, June 27, 2016. REUTERS/Marcelo del Pozo

Actor Leonardo DiCaprio delivers his remarks during the Paris Agreement on climate change held at the United Nations Headquarters in Manhattan, New York, U.S., April 22, 2016. REUTERS/Carlo Allegri 

Actor Leonardo DiCaprio walks away from the podium after delivering his remarks during the Paris Agreement on climate change held at the United Nations Headquarters in Manhattan, New York, U.S., April 22, 2016. REUTERS/Carlo Allegri 

Actor Leonardo DiCaprio delivers his remarks during the Paris Agreement on climate change held at the United Nations Headquarters in Manhattan, New York, U.S., April 22, 2016. REUTERS/Carlo Allegri 

Actor Leonardo DiCaprio delivers his remarks during the Paris Agreement on climate change held at the United Nations Headquarters in Manhattan, New York, U.S., April 22, 2016. REUTERS/Carlo Allegri 

U.S. Secretary of State John Kerry delivers his remarks during the signing ceremony on climate change held at the United Nations Headquarters in Manhattan, New York, U.S., April 22, 2016. REUTERS/Carlo Allegri

Princess Lalla Hasna of Morocco delivers her remarks during the signing ceremony on climate change held at the United Nations Headquarters in Manhattan, New York, U.S., April 22, 2016. REUTERS/Carlo Allegri

U.S. Secretary of State John Kerry delivers his remarks during the signing ceremony on climate change held at the United Nations Headquarters in Manhattan, New York, U.S., April 22, 2016. REUTERS/Carlo Allegri

U.S. Secretary of State John Kerry delivers his remarks during the signing ceremony on climate change held at the United Nations Headquarters in Manhattan, New York, U.S., April 22, 2016. REUTERS/Carlo Allegri