TURKEY-RUSSIA-SYRIA-AMBASSADOR-CONFLICT

Turkish special force police officers stand guard outside the Russian consulate in Istanbul on December 20, 2016, a day after the assassination of the Russian ambassador in the Turkish capital. Russia's ambassador to Ankara was shot dead in a brazen attack by an off-duty Turkish policeman at an art exhibition on December 19 in what both sides branded an "act of terror" aimed at damaging their improving ties. The assassination, by a lone gunman shouting "Allahu Akbar" and "Don't forget Aleppo", came after days of protests in Turkey over Russia's role in Syria and on the eve of a meeting of the foreign ministers of Turkey, Russia and Iran on the conflict. (Photo by YASIN AKGUL / AFP) (Photo by YASIN AKGUL/AFP via Getty Images)