AKIPRESS.COM - A gunman shouting "Do not forget Aleppo!" assassinated Russia's ambassador to Turkey at an Ankara art gallery on Monday in what leaders of Russia and Turkey called a provocative terror attack, CNN reported.

Ambassador Andrey Karlov's shooting was captured in real time in photos and video that quickly spread through the Internet worldwide.

The assassination comes at a time of improved relations and increased cooperation between Russia and Turkey.

Leaders of both countries vowed to not let the assassination cast a shadow over that friendship.

It also comes during a pivotal moment in Syria, where Russia has been instrumental in President Bashar al-Assad's push to retake rebel-held parts of Syria.

In televised remarks, Russian President Vladimir Putin said the killing was a clear "provocation" aimed at undermining not just the normalization of Russia-Turkish relations but the "peace process in Syria" promoted by Russia, Turkey, Iran and other countries.

"The only response we should offer to this murder is stepping up our fight against terror, and the criminals will feel the heat," he said.

Turkish President Recep Tayyip Erdogan echoed Putin's sentiments, saying the assassination was intended to destroy the normalization of Turkey-Russian relations.

"But the Russian government and the Turkish republic have the will to not fall into that provocation."