Russian Ambassador to Turkey Andrey Karlov was assassinated Monday evening at an art exhibition in Ankara, Turkey, in a shooting both Turkish and Russian leaders have called a terrorist attack. Turkish authorities say the lone gunman was a 22-year-old off-duty Turkish police officer. He shot Karlov dead in a dramatic scene in the middle of the art gallery, as he yelled “Don’t forget Aleppo, don’t forget Syria!” The attack came as the Turkish foreign minister was on his way to Moscow, Russia, to meet with his Russian and Iranian counterparts for talks on the ongoing Syrian war. Russia has been backing the Syrian government in its war against anti-government rebels, most notably by launching a months-long bombing campaign against rebel-held eastern Aleppo, which included targeting hospitals and other medical centers. Russia’s bombing campaign helped the Syrian government take over eastern Aleppo last week, marking a decisive battle in the five-year civil war. This is Turkish President Recep Tayyip Erdogan, following the assassination.

President Recep Tayyip Erdogan: “I describe this attack on Russia’s Embassy as an attack on Turkey, Turkey’s state and nation. After the attack on the Russian ambassador, during the talk with Mr. Putin, we agreed this is a provocation, and there isn’t any dispute.”

On Monday, Russian President Vladimir Putin also described the assassination as a “provocation” and said it sought to fray relations between Russia and Turkey.

President Vladimir Putin: “The committed crime is obviously a provocation designed to spoil normalization of Russia-Turkey relations and derailing the peace process in Syria, which is actively promoted by Russia, Turkey, Iran and other countries interested in reconcilement of inter-Syria conflict.”