Russian Ambassador to Turkey Andrey Karlov was assassinated today in the Turkish capital city of Ankara while attending an event at the Ankara Center for Contemporary Art. The killer was identified as Mevlut Mert Altintas, an active member of the Ankara Police Department. Three bystanders were also wounded.

A number of reporters were on scene covering the incident, and a number of photos and video reportedly exists of the assassination. Ambassador Karlov was in the middle of giving a speech when Altintas, who was standing behind him, shot him five times in the back.

The gunman apparently used his police ID to bypass security, but was shot and killed by other police after the assassination. The attacker shouted after the shooting that it was “revenge for Syria and Aleppo.”

While Syria’s Civil War has been a source of acrimony between Turkey and Russia for several years, including a late 2015 incident in which Turkey shot down a Russian warplane over Syrian airspace along the border. The two countries had more recently been trying to improve ties, though clearly this puts a damper on that.

Karlov is the first Russian Ambassador killed anywhere in the world since 1829, when well-known playwright Alexander Griboyedov, then Russian Ambassador to Iran, was killed along with his entire embassy staff when an angry mob stormed the building.

While that was a big deal at the time, backdropped by the Great Game efforts by Britain and Russia to establish greater control over Central Asia, today’s incident is potentially a much bigger deal, as Turkey is a NATO member nation.

Having the Russian Ambassador to a NATO state being assassinated in that nation’s capital city by a member of that nation’s police force looks really bad, particularly given the current level of NATO hostility toward Russia, which itself centers on the same rhetoric around Aleppo.

NATO Secretary-General Jens Stoltenberg was not particularly vocal about the incident, however, simply offering “condolences” and insisting that there was “no justification” for killing the Russian Ambassador. US Secretary of State John Kerry also offered assistance in investigating the assassination.

Turkish Foreign Minister Mevlut Cavusoglu is scheduled to visit Moscow tomorrow for Syria talks, and indications at this point are that the talks will go ahead as planned, though clearly this is going to cast a big shadow over the proceedings.

Turkish officials are also trying to downplay the whole “policeman” part of the assassination, with state media reporters claiming he used an al-Qaeda slogan, a subtle distinction since al-Qaeda’s Nusra Front is backed by Turkey, particularly in Aleppo.

Ankara’s mayor also claimed there was evidence the assassin was in league with the Gulenist movement, though as usual he offered no evidence to this claim, and given the scope of Turkey’s purge of anyone with even suspected Gulenist ties in all aspects of society over the past six months, it’s hard to believe a policeman slipped through the cracks.