Russian Ambassador to Turkey Andrey Karlov was shot in Ankara on Monday.
The envoy was delivering a speech at the opening ceremony of a photo exhibit in Ankara when an armed assailant opened fire on him.
Karlov was shot multiple times and seriously wounded. He later succumbed to his injuries.
"Attack aimed at ruining Turkey's ties with Russia"
Addressing a press conference, President Recep Tayyip Erdogan said Turkey and Russia will form a joint committee to investigate the attack. He said the attack was a provocation aimed at ruining Turkey's ties with Russia.
President Erdogan described the incident as an attack on Russian as well as Turkish people.
Russian President Vladimir Putin said that the envoy's killing targeted Russian-Turkish ties and Syria peace efforts.
President Erdogan earlier spoke to his Russian counterpart and discussed the incident over a telephone conversation.
Speaking to journalists in Moscow, Turkish Foreign Minister Mevlut Cavusoglu said that the attack had not just targeted the Russian ambassador, but also Turkey and Russia who had normalised relations.
Assailant identified as 22-year-old off-duty cop
Speaking to reporters at the site of the attack, Turkish Interior Minister Suleyman Soylu said that the attacker had been identified as a 22-year-old off-duty policeman, who had been working in Ankara for the past two and a half years.
Soylu added that the incident was a "terror attack" on the strong relations between Turkey and Russia. He said Karlov was a trusted friend of the country and that Turkey was deeply saddened by the attack.
The interior minister offered condolences to Russia, and the diplomat's family and added that the motives of the attacker were not known. He further said that three more people were wounded in the attack.
The attack happened at the Cagdas Sanatlar Merkezi, a major art exhibition hall in the Cankaya district of Ankara where most foreign embassies are located including Russia's mission.
Pictures published by the Hurriyet daily showed at least two injured men as another man brandished a gun.
Russia's state-run RIA Novosti news agency quoted a witness, "It is likely that the attack was aimed at the ambassador because after the shots were made the assailant let those present escape the room."
The assailant was later shot dead by security personnel.
"We qualify what happened as a terrorist act," Russian foreign ministry spokesperson Maria Zakharova said. "The murderers will be punished. Today this issue will be raised at the UN Security Council. Terrorism will not win out."
The United Nations and the US Department of State condemned the attack on the Russian diplomat. US Secretary of State John Kerry said the United States was ready to help Russia and Turkey investigate the attack.
Karlov - a career diplomat
Andrey Gennadyevich Karlov was born in 1954 in Moscow.
He graduated from Moscow State Institute of International Relations in 1976. In 1992, he graduated from the Diplomatic Academy.
He worked on different positions in the Ministry of Foreign Affairs of the USSR and Russia, as well as foreign missions.
Karlov has been serving as the Ambassador of Russia to Turkey since July 2013. He is survived by a wife and a son.
Syria talks to continue
Talks about the future of Syria involving Russia, Iran and Turkey will go ahead on Tuesday despite the murder of the Russian ambassador to Ankara, the Interfax news agency cited Leonid Slutsky, a senior parliamentarian, as saying.
The foreign and defence ministers of Russia, Iran and Turkey are due to discuss the future of Syria in Moscow on Tuesday. Slutsky is chairman of the State Duma or lower house of parliament's international affairs committee.