In a stunning act of political violence, a gun-wielding man in a black suit and tie shot and killed Russia’s ambassador to Turkey on Monday in what the assassin described as an act of revenge for Russia’s bombing of civilians in Aleppo, Syria.

Video captured at the scene shows the gunman shouting “Allahu akbar,” the Arabic phrase for “God is great,” as well as the Arabic words for “Remember Syria! Remember Aleppo!” as the ambassador, Andrey Karlov, lies bleeding on the floor next to him. The fallen diplomat had been speaking at the opening of a photographic art exhibition in the capital city of Ankara, titled “Russia through Turks’ eyes.”

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الله اكبر نحن الذين بايعنا محمد على الشهادة

هذا انتقام لسوريا وحلب pic.twitter.com/qG0dSBsqrK — عمر البلخي (@omarbalkhi5) December 19, 2016

Turkey’s Interior Minister Suleyman Soylu identified the gunman as Mevlüt Mert Altıntaş, a 22-year-old Turkish off-duty police officer who has been with the riot police squad in Ankara for the past 2 1/2 years.

He was subsequently shot and killed by Turkish security forces responding to the incident, which Russia’s Foreign Ministry is now calling a “terrorist attack.”

Russia has been actively bombing targets in Syria on behalf of embattled Syrian president and Kremlin ally Bashar al-Assad since September 2015. Russia claims it is bombing legitimate targets held by ISIS and the other “terrorists” who are fighting to topple Assad.

In reality, Russian and Syrian government airstrikes on the city of Aleppo, which has been the central front in the war for the past year, have targeted civilian neighborhoods, schools, hospitals, and humanitarian aid convoys, in addition to ISIS- and rebel-held targets. According to the UK-based Syrian Observatory for Human Rights, over 9,000 people, including nearly 4,000 civilians, have been killed in one year of Russian air raids in Syria.

Turkey is also involved in the war in Syria — although not on the same side as Russia. Turkey is a NATO ally and part of the US-led fight against ISIS in Iraq and Syria. It also supports some rebels who are fighting to oust the Assad regime.

Still, Ankara and Moscow have begun a sort of warming of relations in recent months, with Turkish President Recep Tayyip Erdoğan flying to St. Petersburg in August to meet personally with Vladimir Putin for talks about bilateral trade and energy projects designed to boost both countries’ economies.

It is still too soon to know what long-term impact, if any, the assassination of the Russian ambassador may have on Turkish-Russian relations, or Russia’s policy in Syria. But in the short term, at least, it seems that both Moscow and Ankara are resolved not to let this incident scuttle their burgeoning cooperative relationship.

Both Putin and Erdogan issued statements shortly after the shooting occurred saying that the act had been aimed at disrupting Turkish-Russian relations, with Erdogan stating that “both the Russian and Turkish administrations have the determination not to fall for this provocation.”

Indeed, the shooting occurred just one day before Turkey’s foreign minister was scheduled to fly to Moscow for a meeting with Russian and Iranian diplomats on the situation in Syria. Yet the assassination did not stop the trilateral meeting from going forward as planned, and in fact the three parties — Iran, Russia, and Turkey — were even able to agree on a “joint declaration” to find a solution in Syria as a result of that meeting.

What is certain, though, is that this criminal act makes an already extremely complicated situation even more fragile — and even more dangerous.