The assassination of Ambassador Andrei Karlov in Ankara is painful for Russia, Russian President Vladimir Putin stated on Tuesday, RIA Novosti reports.

“This apparently gives us a special pain,” the Russian leader said, speaking at a concert dedicated to the Day of State Security Body Worker. He also stressed that the diplomat was killed meanly. Thorough investigation is conducted into this fact, the President added.

On Monday evening, a gunman attacked Russian envoy to Turkey, Andrei Karlov, while the latter was giving a speech at a photo exhibition dedicated to Kamchatka at Çağdaş Sanat Merkezi Contemporary Arts Center of Ankara.

The gunman shot the ambassador in the back, following which he uttered words related to Aleppo and Syria as well as shouted “Allahu akbar (God is great).”

Karlov was rushed to hospital in critical condition, but he could not be saved. 

The assailant, who was shot dead by police 45 minutes after the assault, was later identified as Ankara police officer Mevlüt Mert Altıntaş.

Immediately after the incident, the Russian leader instructed to bestow posthumous state award upon the killed diplomat and eternalize his memory.