Ankara: World leaders on Tuesday expressed shock and grief over the killing of Russian ambassador to Turkey Andrei Karlov and termed the assassination a "provocation" and an attempt to disrupt peace.
The Russian ambassador was killed late on Monday by a Turkish policeman in protest against Moscow's involvement in Syria's Aleppo, BBC reported.
It was not clear whether the 22-year-old Mevlut Mert Aydintas had links to any militant group.
The shooter in a video that captured the killing can be heard yelling "Don't forget about Aleppo, don't forget about Syria" and using the Arabic phrase "Allahu Akbar" (God is great).
The killing took place a day after protests erupted in Turkey over Russia's support for Syrian President Bashar al-Assad.
Turkish President Recap Tayyip Erdogan said the attack was aimed at hurting ties with Russia.
Erdogan spoke to Russian President Vladimir Putin over phone and both leaders agreed that it was an act of "provocation".
Putin said the act was "undoubtedly a provocation aimed at disrupting the normalisation" of ties and the "peace process in Syria".
Condemning the attack as an act of "terrorism", Russian Foreign Ministry spokeswoman Maria Zakharova said Turkey had given assurances that there would be a comprehensive investigation, and those responsible would be punished.
The UN Security Council strongly condemned the killing while Secretary General Ban Ki-moon said he was appalled by "this senseless act of terror".
The attack was also condemned by other countries.
US Secretary of State John Kerry said: "We stand ready to offer assistance to Russia and Turkey as they investigate this despicable attack, which was also an assault on the right of all diplomats to safely and securely advance and represent their nations around the world."
"Shocked to hear of despicable murder of Russia's ambassador to Turkey. My thoughts are with his family. I condemn this cowardly attack," British Foreign Secretary Boris Johnson said.
German Interior Minister Thomas de Maiziere said his country stood with Turkey in a common fight against terrorism.
French President Francois Hollande "strongly" condemned the killing.
India's External Affairs Ministry condemned the "dastardly act".
"There can never be any justification for violence and terrorism," ministry spokesperson Vikas Swarup said in a statement.
Chinese Foreign Minister Wang Yi said Beijing firmly opposed terrorism in all forms.
China is willing to work with the international community in firmly supporting Russia's efforts and actions to fight terrorism, Wang said.
The movement of US-based cleric Fethullah Gulen also condemned the attack and rejected any links to the attacker.
Turkey blames the movement for July 15 failed coup aimed against Erdogan.
Sri Lanka's Foreign Minister Mangala Samaraweera said Colombo considered the attack a violation of the right of all diplomats to represent their nations peacefully around the world.
Pakistan condoled the bereaved family of the ambassador, and expressed solidarity with Russia and Turkey.
Taking up the Ankara posting in July 2013, Karlov had to grapple with a major diplomatic crisis last year when a Turkish plane shot down a Russian jet close to the Syrian border.