China's Foreign Minister Wang Yi (3rd R), Dominican Republic's President Danilo Medina (3rd L), Chancellor Miguel Vargas (2nd L) and embassador to China Briunny Garabito Segura (L) attend the opening ceremony of Dominican Republic's embassy in Beijing, November 3, 2018. REUTERS/Thomas Peter/Pool 

China's Foreign Minister Wang Yi (3rd L), Dominican Republic's President Danilo Medina (2nd L), Chancellor Miguel Vargas (L) and embassador to China Briunny Garabito Segura (2nd R) attend the opening ceremony of Dominican Republic's embassy in Beijing, November 3, 2018. REUTERS/Thomas Peter/Pool 

Russian Foreign Minister Sergei Lavrov (R) and his Iranian counterpart Mohammad Javad Zarif lay flowers in memory of murdered Russian ambassador to Turkey Andrei Karlov before their talks in Moscow, Russia, December 20, 2016. REUTERS/Maxim Shemetov 

Russian Foreign Minister Sergei Lavrov lays flowers in memory of murdered Russian ambassador to Turkey Andrei Karlov before the talks with Iranian Foreign Minister Mohammad Javad Zarif in Moscow, Russia, December 20, 2016. REUTERS/Maxim Shemetov 

Russian Foreign Minister Sergei Lavrov (R) and his Iranian counterpart Mohammad Javad Zarif lay flowers in memory of murdered Russian ambassador to Turkey Andrei Karlov before their talks in Moscow, Russia, December 20, 2016. REUTERS/Maxim Shemetov 

Turkish Foreign Minister Mevlut Cavusoglu lays flowers in memory of murdered Russian ambassador to Turkey Andrei Karlov before the talks with Russian Foreign Minister Sergei Lavrov in Moscow, Russia, December 20, 2016. REUTERS/Maxim Shemetov 

Flowers are placed near a portrait of murdered Russian ambassador to Turkey Andrei Karlov during a meeting of Russian Foreign Minister Sergei Lavrov with his Turkish counterpart Mevlut Cavusoglu in Moscow, Russia, December 20, 2016. REUTERS/Maxim Shemetov 

Russian Foreign Minister Sergei Lavrov (R) and his Turkish counterpart Mevlut Cavusoglu attend a ceremony in memory of murdered Russian ambassador to Turkey Andrei Karlov before their talks in Moscow, Russia, December 20, 2016. REUTERS/Maxim Shemetov 

Russian Foreign Minister Sergei Lavrov (R) and his Turkish counterpart Mevlut Cavusoglu lay flowers in memory of murdered Russian ambassador to Turkey Andrei Karlov before their talks in Moscow, Russia, December 20, 2016. REUTERS/Maxim Shemetov TPX IMAGES OF THE DAY 

French President Francois Hollande (R rear) and Slovakia's President Andrej Kiska (L rear) stand behind France's ambassador to Slovakia, Christophe Leonzi (R), and Slovakia's ambassador to France, Marek Estok (L), as they sign agreements during a meeting at the Elysee Palace in Paris, France, November 22, 2016. REUTERS/Stephane De Sakutin/Pool 

Queen Elizabeth II receives His Excellency Mr Koji Tsuruoka the ambassador of Japan, who was accompanied by his wife Mrs Tsuruoka, during a private audience during which he presented his Letters of Credence at Buckingham Palace in central London, Britain October 20, 2016. REUTERS/John Stillwell/Pool

Queen Elizabeth II receives His Excellency Mr Koji Tsuruoka the ambassador of Japan, who was accompanied by his wife Mrs Tsuruoka, during a private audience during which he presented his Letters of Credence at Buckingham Palace in central London, Britain October 20, 2016. REUTERS/John Stillwell/Pool

Queen Elizabeth II shakes hands with His Excellency Mr Koji Tsuruoka the ambassador of Japan, who was accompanied by his wife Mrs Tsuruoka, during a private audience during which he presented his Letters of Credence at Buckingham Palace in central London, Britain October 20, 2016. REUTERS/John Stillwell/Pool

FILE PHOTO - U.S. President Barack Obama and his wife Michelle stand with U.S. ambassador to Cuba, Jeffrey DeLaurentis (L), as they meet with embassy staff in a hotel in Havana March 20, 2016. REUTERS/Carlos Barria/File Photo 

Russian Ambassador to the United Nations Vitaly Churkin (L) speaks with Syrian Ambassador to the United Nations Bashar al-Jaafari before a meeting of the United Nations Security Council during the 71st session of the U.N. General Assembly at U.N. headquarters in New York, U.S., September 21, 2016. REUTERS/Lucas Jackson

Russian Ambassador to the United Nations Vitaly Churkin (L) speaks with Syrian Ambassador to the United Nations Bashar al-Jaafari before a meeting of the United Nations Security Council during the 71st session of the U.N. General Assembly at U.N. headquarters in New York, U.S., September 21, 2016. REUTERS/Lucas Jackson

Colombia's President Juan Manuel Santos, Colombia's Ambassador to the U.N. Maria Emma Mejia (C) and Colombia's Foreign Minister Maria Angela Olguin attend the Global Demining Initiative for Colombia in New York, U.S., September 18, 2016. REUTERS/Eduardo Munoz 

South Korean Ambassador Hahn Choong-hee (C) speaks to the press next to Japanese Ambassador Koro Bessho (R) and U.S. Ambassador Samantha Power following the United Nations Security Council closed door meeting to discuss the latest missile launches by North Korea at the United Nations in Manhattan, New York, U.S., September 6, 2016. REUTERS/Darren Ornitz TPX IMAGES OF THE DAY

Publisher Kai Diekmann (L) and Israeli ambassador to Germany Yakov Hadas-Handelsman attend the Bild 100 event in Berlin, Germany, September 6, 2016. REUTERS/Stefanie Loos 

U.S. Ambassador to Germany John Emerson and his wife Kimberly attend the Bild 100 event in Berlin, Germany, September 6, 2016. REUTERS/Stefanie Loos 

Japanese Ambassador Koro Bessho speaks to the press with South Korean Ambassador Hahn Choong-hee (not pictured) and U.S. Ambassador Samantha Power (not pictured) following the United Nations Security Council closed door meeting to discuss the latest missile launches by North Korea at the United Nations in Manhattan, New York, U.S., September 6, 2016. REUTERS/Darren Ornitz 

South Korean Ambassador Hahn Choong-hee speaks to the press with Japanese Ambassador Koro Bessho (not pictured) and U.S. Ambassador Samantha Power (not pictured) following the United Nations Security Council closed door meeting to discuss the latest missile launches by North Korea at the United Nations in Manhattan, New York, U.S., September 6, 2016. REUTERS/Darren Ornitz 

Japanese Ambassador Koro Bessho (R) speaks to the press with U.S. Ambassador Samantha Power (L) and South Korean Ambassador Hahn Choong-hee (not pictured) following the United Nations Security Council closed door meeting to discuss the latest missile launches by North Korea at the United Nations in Manhattan, New York, U.S., September 6, 2016. REUTERS/Darren Ornitz 

Japanese Ambassador Koro Bessho (R) speaks to the press next to South Korean Ambassador Hahn Choong-hee (L) and U.S. Ambassador Samantha Power (not pictured) following the United Nations Security Council closed door meeting to discuss the latest missile launches by North Korea at the United Nations in Manhattan, New York, U.S., September 6, 2016. REUTERS/Darren Ornitz 

South Korean Ambassador Hahn Choong-hee (L) speaks to the press next to Japanese Ambassador Koro Bessho (R) and U.S. Ambassador Samantha Power (not pictured) following the United Nations Security Council closed door meeting to discuss the latest missile launches by North Korea at the United Nations in Manhattan, New York, U.S., September 6, 2016. REUTERS/Darren Ornitz 

British Ambassador to the United Nations Matthew Rycroft addresses reporters after the United Nations Security Council closed door meeting to discuss the latest missile launches by North Korea at the United Nations in Manhattan, New York, U.S., September 6, 2016. REUTERS/Darren Ornitz 

Chinese Ambassador to the United Nations Liu Jieyi speaks to reporters before the United Nations Security Council closed door meeting to discuss the latest missile launches by North Korea at the United Nations in Manhattan, New York, U.S., September 6, 2016. REUTERS/Darren Ornitz 

Permanent Representative of France to the United Nations Francois Delattre speaks to reporters before the United Nations Security Council closed door meeting to discuss the latest missile launches by North Korea at the United Nations in Manhattan, New York, U.S., September 6, 2016. REUTERS/Darren Ornitz 

Permanent Representative of Japan to the United Nations Koro Bessho speaks to reporters before the United Nations Security Council closed door meeting to discuss the latest missile launches by North Korea at the United Nations in Manhattan, New York, U.S., September 6, 2016. REUTERS/Darren Ornitz 

Former Philippine President Fidel Ramos (R) and Chinese Ambassador to the Philippines Zhao Jianhua pose for a picture 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 

Gerard Araud (2nd R rear), Ambassador of France to the United States, looks on as U.S. President Barack Obama greets the audience at the Diplomatic Corps Reception at the White House in Washington, U.S., July 15, 2016. REUTERS/Yuri Gripas

U.S. President Barack Obama (L) shakes hands with Gerard Araud, Ambassador of France to the United States, at the Diplomatic Corps Reception at the White House in Washington, U.S., July 15, 2016. REUTERS/Yuri Gripas

Gerard Araud (R), Ambassador of France to the United States, listens to U.S. President Barack Obama speaking about the Bastille Day truck attack in Nice at the Diplomatic Corps Reception at the White House in Washington, U.S., July 15, 2016. REUTERS/Yuri Gripas

Gerard Araud (R), Ambassador of France to the United States, listens to U.S. President Barack Obama speaking about the Bastille Day truck attack in Nice at the Diplomatic Corps Reception at the White House in Washington, U.S., July 15, 2016. REUTERS/Yuri Gripas

Gerard Araud (L), Ambassador of France to the United States, listens to U.S. President Barack Obama speaking about the Bastille Day truck attack in Nice at the Diplomatic Corps Reception at the White House in Washington, U.S., July 15, 2016. REUTERS/Yuri Gripas

Russian ambassador to NATO Alexander Grushko addresses a news conference after the NATO-Russia Council at the Alliance headquarters in Brussels, Belgium, July 13, 2016. REUTERS/Francois Lenoir 

Russian ambassador to NATO Alexander Grushko addresses a news conference after the NATO-Russia Council at the Alliance headquarters in Brussels, Belgium July 13, 2016. REUTERS/Francois Lenoir 

Russian ambassador to NATO Alexander Grushko addresses a news conference after the NATO-Russia Council at the Alliance headquarters in Brussels, Belgium July 13, 2016. REUTERS/Francois Lenoir 

Russian ambassador to NATO Alexander Grushko addresses a news conference after the NATO-Russia Council at the Alliance headquarters in Brussels, Belgium, July 13, 2016. REUTERS/Francois Lenoir 

Russian ambassador to NATO Alexander Grushko addresses a news conference after the NATO-Russia Council at the Alliance headquarters in Brussels, Belgium, July 13, 2016. REUTERS/Francois Lenoir 

U.S. ambassador to Bangladesh Marcia Bernicat (L) talks to Italian ambassador to Bangladesh Mario Palma as Japanese ambassador to Bangladesh Masato Watanabe (R) watches during a memorial ceremony for the victims who were killed in the attack on the Holey Artisan Bakery and the O'Kitchen Restaurant, in Dhaka, Bangladesh, July 4, 2016. REUTERS/Adnan Abidi 

U.S. ambassador to Bangladesh Marcia Bernicat (L) talks to Italian ambassador to Bangladesh Mario Palma during a memorial ceremony for the victims who were killed in the attack on the Holey Artisan Bakery and the O'Kitchen Restaurant, in Dhaka, Bangladesh, July 4, 2016. REUTERS/Adnan Abidi 

Bangladesh's Prime Minister Sheikh Hasina (2nd R) talks to Japanese ambassador to Bangladesh Masato Watanabe (2nd L) after paying homage to the victims who were killed in the attack on the Holey Artisan Bakery and the O'Kitchen Restaurant, during a memorial ceremony in Dhaka, Bangladesh, July 4, 2016. REUTERS/Adnan Abidi 

Japanese ambassador to Bangladesh Masato Watanabe pays homage in front of the coffin of a victim who was killed in the attack on the Holey Artisan Bakery and the O'Kitchen Restaurant, during a memorial ceremony in Dhaka, Bangladesh, July 4, 2016. REUTERS/Adnan Abidi TPX IMAGES OF THE DAY

Japanese ambassador to Bangladesh Masato Watanabe pays homage in front of the coffin of a victim who was killed in the attack on the Holey Artisan Bakery and the O'Kitchen Restaurant, during a memorial ceremony in Dhaka, Bangladesh, July 4, 2016. REUTERS/Adnan Abidi 

Spain's Queen Letizia signs a condolence book for the victims of the Orlando mass shooting next to Spain's King Felipe and U.S. Embassador to Spain James Costos at the U.S. embassy in Madrid, Spain, June 14, 2016. REUTERS/Chema Moya/Pool 

Spain's King Felipe signs a condolence book for the victims of the Orlando mass shooting next to Spain's Queen Letizia and U.S. Embassador to Spain James Costos at the U.S. embassy in Madrid, Spain, June 14, 2016. REUTERS/Chema Moya/Pool 

Russian ambassador to Afghanistan Alexander Mantytskiy speaks during a news conference at the Russian embassy in Kabul, Afghanistan, April 25, 2016. REUTERS/Omar Sobhani 

Russian ambassador to Afghanistan Alexander Mantytskiy speaks during a news conference at the Russian embassy in Kabul, Afghanistan, April 25, 2016. REUTERS/Omar Sobhani 

Bangladesh's Ambassador to the Philippines John Gomes talks to reporters after attending a Senate hearing of money laundering involving $81 million stolen from Bangladesh's central bank, at the Philippine Senate in Manila April 19, 2016. REUTERS/Erik De Castro 

U.S. Ambassador to Iraq Stuart Jones (center L) walks with Secretary of State John Kerry (center R) as he arrives via military transport at Baghdad International Airport in Baghdad April 8, 2016. REUTERS/Jonathan Ernst TPX IMAGES OF THE DAY

George Twopointoh (C), brand ambassador for Genworth, guides Ugo Dumont, a volunteer for the Genworth R70i Aging Experience, during a demonstration at the Liberty Science Center in Jersey City, New Jersey April 5, 2016. REUTERS/Shannon Stapleton 

A Genworth brand ambassador points to a hearing display during a Genworth R70i Aging Experience demonstration at the Liberty Science Center in Jersey City, New Jersey, April 5, 2016. REUTERS/Shannon Stapleton 

So Se Pyong, North Korea's ambassador to the United Nations in Geneva, addresses a news conference at the Permanent Mission of North Korea in Geneva, Switzerland in this February 11, 2014 file picture. To match Exclusive NORTHKOREA-NUCLEAR/ENVOY REUTERS/Denis Balibouse/Files TPX IMAGES OF THE DAY

Chinese ambassador to South Korea Qiu Guohong covers caskets containing the remains of Chinese soldiers, with a Chinese national flag, during the handing over ceremony of the remains at the Incheon International Airport in Incheon, South Korea, March 31, 2016. REUTERS/Kim Hong-Ji 

Indonesia's Foreign Minister Retno Marsudi makes a statement at the Foreign Ministry in Jakarta, Indonesia March 21, 2016. Indonesia protested on Monday against what it described as an infringement of its waters by a Chinese coast guard vessel near a disputed area of the South China Sea at the weekend, the foreign minister in Jakarta said.REUTERS/Darren Whiteside TPX IMAGES OF THE DAY 

Indonesia's Foreign Minister Retno Marsudi (R) and her Australian counterpart Julie Bishop address the media following their meeting in Jakarta, Indonesia March 21, 2016. REUTERS/Darren Whiteside

Indonesia's Foreign Minister Retno Marsudi (R) and her Australian counterpart Julie Bishop leave the podiums after addressing the media following their meeting in Jakarta, Indonesia March 21, 2016. REUTERS/Darren Whiteside

Indonesia's Foreign Minister Retno Marsudi (R) walks with her Australian counterpart Julie Bishop following their meeting in Jakarta, Indonesia March 21, 2016. REUTERS/Darren Whiteside

Indonesia's Foreign Minister Retno Marsudi (R) and her Australian counterpart Julie Bishop address the media following their meeting in Jakarta, Indonesia March 21, 2016. REUTERS/Darren Whiteside