Russia's ambassador to Turkey, Andrey Karlov, was shot to death in the Turkish capital of Ankara on Dec. 19 by an off-duty Turkish policeman who shouted "Don't forget Aleppo!"after shooting Karlov in the back.
The policeman, who was identified as Mevlüt Mert Altıntaş, was later shot dead by security personnel. Karlov was visiting an art gallery at the time of his assassination. Altıntaş, who was dressed in a suit and tie, shot Karlov at point-blank range while the ambassador was delivering his speech.
Karlov's death comes less than a week after the fall of the city of Aleppo in Syria, long a bastion for forces battling to oust Syrian dictator Bashar al-Assad, who is backed by Russia. Indiscriminate and massive Russian aerial bombing of Aleppo, which also slaughtered thousands of civilians, helped lead to the fall of the city to Assad.
Russia's foreign ministry announced Karlov had died of his injuries. Karlov was appointed Russian ambassador to Turkey in July 2013.
A video of the attack showed Altıntaş, 22, yelling, "Don't forget Aleppo. Don't forget Syria!" and "Allahu Akbar" (God is Greatest) while holding a gun in one hand and waving the other in the air.
Altıntaş also shouted, "Stand back! Stand back! Only death will take me out of here. Anyone who has a role in this oppression will die one by one."
A graphic video showing Karlov being killed by Altıntaş can be viewed here.
Russian President Vladimir Putin said on TV that Karlov's assassination was an "open provocation" aimed at undermining the search for peace in Syria and the normalization of ties with Turkey.
He said Russia's response will be a stronger attack on terrorism.
"This murder is clearly a provocation aimed at undermining the improvement and normalization of Russian-Turkish relations, as well as undermining the peace process in Syria promoted by Russia, Turkey, Iran and other countries interested in settling the conflict in Syria," said Putin.
Turkish president Recep Tayyip Erdogan said Turkey and Russia will jointly investigate the attack and won't allow it to disrupt ties between both nations.