MOSCOW, RUSSIA - DECEMBER 22: Marina Karlova (left 3), wife of the slain ambassador Andrey Karlov, is seen during funeral service in Christ the Savior Cathedral in Moscow, Russia, on December 22, 2016. Karlov was delivering a speech at the opening ceremony of a photo exhibit when an armed assailant 22-year-old riot police officer Mevlut Mert Altintas opened fire on him. Assailant has been killed by the Turkish police during a fire exchange at the crime scene. ( Nikita Shvetsov - Anadolu Agency )

MOSCOW, RUSSIA - DECEMBER 22: Patriarch Kirill of Moscow and all Russia conducts funeral service for Russia's ambassador to Turkey Andrey ​Karlov, in Christ the Savior Cathedral in Moscow, Russia, on December 22, 2016. Karlov was delivering a speech at the opening ceremony of a photo exhibit when an armed assailant 22-year-old riot police officer Mevlut Mert Altintas opened fire on him. Assailant has been killed by the Turkish police during a fire exchange at the crime scene. ( Nikita Shvetsov - Anadolu Agency )

MOSCOW, RUSSIA - DECEMBER 22: Funeral service for Russia's ambassador to Turkey Andrey ​Karlov, is held in Christ the Savior Cathedral in Moscow, Russia, on December 22, 2016. Karlov was delivering a speech at the opening ceremony of a photo exhibit when an armed assailant 22-year-old riot police officer Mevlut Mert Altintas opened fire on him. Assailant has been killed by the Turkish police during a fire exchange at the crime scene. ( Kremlin Press Office - Anadolu Agency )

MOSCOW, RUSSIA - DECEMBER 22: Russian President Vladimir Putin, stands behind the coffin during funeral service for Russia's ambassador to Turkey Andrey ​Karlov, in Christ the Savior Cathedral in Moscow, Russia, on December 22, 2016. Karlov was delivering a speech at the opening ceremony of a photo exhibit when an armed assailant 22-year-old riot police officer Mevlut Mert Altintas opened fire on him. Assailant has been killed by the Turkish police during a fire exchange at the crime scene. ( Kremlin Press Office - Anadolu Agency )

MOSCOW, RUSSIA - DECEMBER 22: Valentina Matviyenko (C), head of the Upper House of the Russian Federation, stands behind the coffin during funeral service for Russia's ambassador to Turkey Andrey ​Karlov, in Christ the Savior Cathedral in Moscow, Russia, on December 22, 2016. Karlov was delivering a speech at the opening ceremony of a photo exhibit when an armed assailant 22-year-old riot police officer Mevlut Mert Altintas opened fire on him. Assailant has been killed by the Turkish police during a fire exchange at the crime scene. ( Kremlin Press Office - Anadolu Agency )

MOSCOW, RUSSIA - DECEMBER 22: Wife of Russia's ambassador to Turkey Andrey ​Karlov, Marina Karlova (left 2) attends funeral ceremony for Andrey ​Karlov at Russian Foreign Ministry in Moscow, Russia on December 22, 2016. Russian Ambassador to Turkey Andrei Karlov has been shot multiple times at an exhibition in Ankara and died, on December 19, 2016. Karlov was delivering a speech at the opening ceremony of a photo exhibit when an armed assailant 22-year-old riot police officer Mevlut Mert Altintas opened fire on him. Assailant has been killed by the Turkish police during a fire exchange at the crime scene. ( Sefa Karacan - Anadolu Agency )

MOSCOW, RUSSIA - DECEMBER 22: Soldiers carry the coffin of Russia's ambassador to Turkey Andrey ​Karlov during funeral ceremony at Russian Foreign Ministry in Moscow, Russia on December 22, 2016. Russian Ambassador to Turkey Andrei Karlov has been shot multiple times at an exhibition in Ankara and died, on December 19, 2016. Karlov was delivering a speech at the opening ceremony of a photo exhibit when an armed assailant 22-year-old riot police officer Mevlut Mert Altintas opened fire on him. Assailant has been killed by the Turkish police during a fire exchange at the crime scene. ( Sefa Karacan - Anadolu Agency )

MOSCOW, RUSSIA - DECEMBER 22: Soldiers carry the coffin of Russia's ambassador to Turkey Andrey ​Karlov during funeral ceremony at Russian Foreign Ministry in Moscow, Russia on December 22, 2016. Russian Ambassador to Turkey Andrei Karlov has been shot multiple times at an exhibition in Ankara and died, on December 19, 2016. Karlov was delivering a speech at the opening ceremony of a photo exhibit when an armed assailant 22-year-old riot police officer Mevlut Mert Altintas opened fire on him. Assailant has been killed by the Turkish police during a fire exchange at the crime scene. ( Sefa Karacan - Anadolu Agency )